28889766034467624
28,889,766,034,467,624 is an even composite number composed of six prime numbers multiplied together.
What does the number 28889766034467624 look like?
This visualization shows the relationship between its 6 prime factors (large circles) and 2016 divisors.
28889766034467624 is an even composite number. It is composed of six distinct prime numbers multiplied together. It has a total of two thousand and sixteen divisors.
Prime factorization of 28889766034467624:
23 × 36 × 11 × 132 × 23 × 415
(2 × 2 × 2 × 3 × 3 × 3 × 3 × 3 × 3 × 11 × 13 × 13 × 23 × 41 × 41 × 41 × 41 × 41)See below for interesting mathematical facts about the number 28889766034467624 from the Numbermatics database.
Names of 28889766034467624
- Cardinal: 28889766034467624 can be written as Twenty-eight quadrillion, eight hundred eighty-nine trillion, seven hundred sixty-six billion, thirty-four million, four hundred sixty-seven thousand, six hundred twenty-four.
Scientific notation
- Scientific notation: 2.8889766034467624 × 1016
Factors of 28889766034467624
Divisors of 28889766034467624
- Number of divisors d(n): 2016
-
Complete list of divisors:
1 2 3 4 6 8 9 11 12 13 18 22 23 24 26 27 33 36 39 41 44 46 52 54 66 69 72 78 81 82 88 92 99 104 108 117 123 132 138 143 156 162 164 169 184 198 207 216 234 243 246 253 264 276 286 297 299 312 324 328 338 351 369 396 414 429 451 468 486 492 506 507 533 552 572 594 598 621 648 676 702 729 738 759 792 828 858 891 897 902 936 943 972 984 1012 1014 1053 1066 1107 1144 1188 1196 1242 1287 1352 1353 1404 1458 1476 1518 1521 1599 1656 1681 1716 1782 1794 1804 1859 1863 1886 1944 2024 2028 2106 2132 2214 2277 2376 2392 2484 2574 2673 2691 2706 2808 2829 2916 2952 3036 3042 3159 3198 3289 3321 3362 3432 3564 3588 3608 3718 3726 3772 3861 3887 4056 4059 4212 4264 4428 4554 4563 4797 4968 5043 5148 5346 5382 5412 5577 5589 5658 5832 5863 6072 6084 6318 6396 6578 6642 6724 6831 6929 7128 7176 7436 7452 7544 7722 7774 8019 8073 8118 8424 8487 8856 9108 9126 9477 9594 9867 9963 10086 10296 10373 10692 10764 10824 11154 11178 11316 11583 11661 11726 12168 12177 12259 12636 12792 13156 13284 13448 13662 13689 13858 14391 14872 14904 15129 15444 15548 16038 16146 16236 16731 16767 16974 17589 18216 18252 18491 18954 19188 19734 19926 20172 20493 20746 20787 21384 21528 21853 22308 22356 22632 23166 23322 23452 24219 24354 24518 25272 25461 26312 26568 27324 27378 27716 28782 29601 29889 30258 30888 31096 31119 32076 32292 32472 33462 33534 33948 34749 34983 35178 36504 36531 36777 36982 37908 38376 38663 39468 39852 40344 40986 41067 41492 41574 42757 43173 43706 44616 44712 45387 46332 46644 46904 48438 48708 49036 50193 50922 52767 54648 54756 55432 55473 57564 59202 59778 60516 61479 62238 62361 64152 64584 65559 66924 67068 67896 68921 69498 69966 70356 72657 73062 73554 73964 75816 76219 76383 77326 78936 79704 81972 82134 82984 83148 85514 86346 87412 88803 90774 92664 93288 93357 96876 97416 98072 100386 101844 104247 104949 105534 109512 109593 110331 110946 115128 115989 118404 119556 121032 122958 123201 124476 124722 128271 129519 131118 133848 134136 134849 136161 137842 138996 139932 140712 145314 146124 147108 147928 150579 152438 152766 154652 158301 159367 163944 164268 166296 166419 171028 172692 174824 177606 181548 184437 186714 187083 193752 196677 200772 203688 206763 208494 209898 211068 217971 219186 220662 221892 228657 229149 231978 236808 239112 240383 245916 246402 248952 249444 256542 259038 262236 266409 269698 272322 275684 277992 279864 280071 284089 290628 292248 294216 301158 304876 305532 309304 314847 316602 318734 328536 328779 330993 332838 342056 345384 347967 355212 363096 368874 373428 374166 384813 388557 393354 401544 404547 408483 413526 416988 419796 422136 425293 435942 438372 441324 443784 451737 457314 458298 463956 474903 478101 480766 491832 492804 498888 499257 502619 513084 518076 524472 532818 539396 544644 551368 560142 561249 568178 581256 590031 602316 609752 611064 620289 629694 633204 637468 657558 661986 665676 685971 687447 695934 710424 721149 737748 746856 748332 758131 769626 777114 786708 799227 809094 816966 827052 833976 839592 840213 850586 852267 871884 876744 882648 895973 903474 914628 916596 927912 944541 949806 956202 961532 985608 992979 998514 1005238 1026168 1036152 1043901 1065636 1078792 1089288 1120284 1122498 1136356 1154439 1180062 1204632 1213641 1225449 1240578 1259388 1266408 1274936 1275879 1315116 1323972 1331352 1355211 1371942 1374894 1391868 1424709 1434303 1442298 1475496 1496664 1497771 1507857 1516262 1539252 1554228 1573416 1585183 1598454 1618188 1633932 1654104 1680426 1683747 1701172 1704534 1743768 1753037 1770093 1791946 1806948 1829256 1833192 1860867 1889082 1899612 1912404 1923064 1985958 1997028 2010476 2057913 2087802 2131272 2163447 2240568 2244996 2272712 2274393 2308878 2360124 2397681 2427282 2450898 2481156 2518776 2520639 2551758 2556801 2630232 2647944 2687919 2710422 2743884 2749788 2783736 2825761 2833623 2849418 2868606 2884596 2978937 2995542 3015714 3032524 3078504 3108456 3124979 3131703 3170366 3196908 3236376 3267864 3360852 3367494 3402344 3409068 3463317 3506074 3540186 3583892 3613896 3640923 3721734 3778164 3799224 3824808 3827637 3971916 3994056 4020952 4115826 4175604 4274127 4302909 4326894 4489992 4493313 4523571 4548786 4617756 4720248 4755549 4795362 4854564 4901796 4962312 5041278 5051241 5103516 5113602 5259111 5310279 5375838 5420844 5487768 5499576 5528809 5582601 5651522 5667246 5698836 5737212 5769192 5957874 5991084 6031428 6065048 6173739 6249958 6263406 6340732 6393816 6490341 6534047 6721704 6734988 6818136 6823179 6926634 7012148 7080372 7167784 7281846 7443468 7556328 7561917 7655274 7670403 7943832 8063757 8231652 8351208 8477283 8548254 8605818 8653788 8936811 8986626 9047142 9097572 9235512 9374937 9395109 9511098 9590724 9709128 9803592 9855703 10082556 10102482 10207032 10227204 10389951 10518222 10620558 10751676 10841688 10922769 11057618 11165202 11303044 11334492 11397672 11474424 11482911 11647649 11915748 11982168 12062856 12347478 12499916 12526812 12681464 12908727 12980682 13068094 13469976 13479939 13570713 13646358 13853268 14024296 14160744 14266647 14563692 14886936 15123834 15310548 15340806 15777333 15930837 16127514 16463304 16586427 16747803 16954566 17096508 17211636 17307576 17437013 17873622 17973252 18094284 18195144 18521217 18749874 18790218 19022196 19181448 19471023 19602141 19711406 20165112 20204964 20454408 20469537 20607379 20779902 21036444 21241116 21503352 21845538 22115236 22330404 22606088 22668984 22965822 23011209 23295298 23831496 24191271 24694956 24999832 25053624 25431849 25817454 25961364 26136188 26959878 27141426 27292716 27706536 28124811 28185327 28533294 29127384 29567109 30247668 30621096 30681612 31083371 31169853 31554666 31861674 32255028 32768307 33172854 33495606 33909132 34193016 34423272 34448733 34874026 34942947 35747244 35946504 36188568 36734893 37042434 37499748 37580436 38044392 38726181 38942046 39204282 39422812 40409928 40712139 40939074 41214758 41559804 42072888 42482232 42799941 43691076 44230472 44660808 45931644 46022418 46590596 47331999 48382542 49389912 49759281 50243409 50863698 51634908 51922728 52272376 52311039 53919756 54282852 54585432 55563651 56249622 56370654 57066588 58413069 58806423 59134218 60495336 61363224 61408611 61822137 62166742 62339706 63109332 63723348 64510056 64992503 65536614 66345708 66991212 67818264 68897466 69033627 69748052 69885894 71494488 71874517 72573813 73469786 74084868 74999496 75160872 76295547 77452362 77884092 78408564 78845624 81424278 81878148 82429516 83119608 84374433 85599882 87382152 88701327 91863288 92044836 93181192 93250113 94663998 96765084 98304921 99518562 100486818 101727396 103269816 103346199 104622078 104828841 107839512 108565704 110204679 111127302 112499244 112741308 114133176 115856201 116178543 116826138 117612846 118268436 122136417 122817222 123644274 124333484 124679412 126218664 127446696 128124139 128399823 129985006 131073228 132691416 133982424 137794932 138067254 139496104 139771788 141995997 143749034 145147626 146939572 148169736 149277843 152591094 154904724 155768184 156817128 156933117 162848556 163756296 164859032 168748866 171199764 175239207 176419269 177402654 184089672 184225833 185466411 186500226 189327996 193530168 194977509 196609842 199037124 200973636 203454792 206692398 207100881 209244156 209657682 215623551 217721439 220409358 222254604 224998488 225482616 226681169 228886641 231712402 232357086 233652276 235225692 236536872 244272834 245634444 247288548 248666968 249358824 253123299 256248278 256799646 259970012 262146456 266103981 267895927 275589864 276134508 279543576 279750339 283991994 287498068 290295252 293879144 298555686 305182188 309809448 310038597 313866234 314486523 325697112 330614037 337497732 342399528 347568603 350478414 352838538 354805308 366409251 368451666 370932822 373000452 378655992 384372417 385199469 389955018 393219684 398074248 401947272 404083823 413384796 414201762 418488312 419315364 425987991 431247102 435442878 440818716 444509208 447833529 453362338 457773282 463424804 464714172 467304552 470451384 470799351 477553609 488545668 491268888 494577096 506246598 512496556 513599292 519940024 529257807 532207962 535791854 552269016 552677499 556399233 559500678 567983988 574996136 580590504 584932527 597111372 610364376 620077194 627732468 628973046 646870653 653164317 661228074 674995464 680043507 686659923 695137206 700956828 705677076 709610616 714917533 732818502 736903332 741865644 746000904 759369897 768744834 770398938 779910036 786439368 798311943 803687781 808167646 826769592 828403524 838630728 839251017 844902539 851975982 862494204 870885756 881637432 895667058 906724676 915546564 926849608 929428344 941598702 943459569 955107218 977091336 991842111 1012493196 1024993112 1027198584 1042705809 1058515614 1064415924 1071583708 1105354998 1112798466 1119001356 1135967976 1153117251 1155598407 1169865054 1194222744 1212251469 1240154388 1255464936 1257946092 1274418211 1277963973 1293741306 1306328634 1322456148 1343500587 1360087014 1373319846 1390274412 1401913656 1411354152 1412398053 1429835066 1432660827 1465637004 1473806664 1483731288 1506130613 1518739794 1537489668 1540797876 1559820072 1587773421 1596623886 1607375562 1616335292 1656807048 1669197699 1678502034 1689805078 1703951964 1724988408 1741771512 1754797581 1791334116 1813449352 1831093128 1883197404 1886919138 1910214436 1940611959 1983684222 2024986392 2040130521 2059979769 2085411618 2117031228 2128831848 2143167416 2144752599 2210709996 2225596932 2238002712 2278109691 2306234502 2311196814 2339730108 2394935829 2411063343 2424502938 2480308776 2515892184 2517753051 2534707617 2548836422 2555927946 2587482612 2612657268 2644912296 2664692623 2687001174 2720174028 2746639692 2780548824 2824796106 2830378707 2859670132 2865321654 2931274008 2946855197 2975526333 3012261226 3037479588 3074979336 3081595752 3128117427 3175546842 3193247772 3214751124 3232670584 3338395398 3357004068 3379610156 3407903928 3459351753 3509595162 3582668232 3636754407 3766394808 3773838276 3820428872 3823254633 3881223918 3967368444 4030501761 4080261042 4119959538 4170823236 4234062456 4237194159 4289505198 4297982481 4421419992 4451193864 4518391839 4556219382 4612469004 4622393628 4679460216 4763320263 4789871658 4822126686 4849005876 5007593097 5035506102 5069415234 5097672844 5111855892 5174965224 5225314536 5253089699 5264392743 5329385246 5374002348 5440348056 5493279384 5649592212 5660757414 5719340264 5730643308 5821835877 5893710394 5951052666 6024522452 6074959176 6120391563 6256234854 6351093684 6386495544 6429502248 6434257797 6676790796 6714008136 6759220312 6918703506 7019190324 7184807487 7233190029 7273508814 7547676552 7553259153 7604122851 7646509266 7762447836 7934736888 7994077869 8061003522 8160522084 8239919076 8341646472 8474388318 8491136121 8579010396 8595964962 8840565591 8926578999 9036783678 9112438764 9224938008 9244787256 9293927929 9384352281 9526640526 9579743316 9644253372 9698011752 10015186194 10071012204 10138830468 10195345688 10223711784 10378055259 10506179398 10528785486 10658770492 10748004696 10910263221 10983733007 11299184424 11321514828 11461286616 11469763899 11643671754 11787420788 11902105332 12049044904 12240783126 12512469708 12702187368 12711582477 12868515594 12893947443 13353581592 13555175517 13837407012 14038380648 14369614974 14466380058 14547017628 15022779291 15106518306 15208245702 15293018532 15524895672 15759269097 15793178229 15988155738 16122007044 16321044168 16479838152 16567436743 16948776636 16982272242 17158020792 17191929924 17465507631 17681131182 17853157998 18073567356 18224877528 18361174689 18587855858 18768704562 19053281052 19159486632 19288506744 19302773391 19579697969 20030372388 20142024408 20277660936 20756110518 21012358796 21057570972 21317540984 21699570087 21820526442 21967466014 22643029656 22659777459 22812368553 22939527798 23287343508 23574841576 23804210664 23982233607 24481566252 25024939416 25423164954 25737031188 25787894886 26521696773 26779736997 27110351034 27674814024 27881783787 28153056843 28739229948 28932760116 29094035256 29311618853 30045558582 30213036612 30416491404 30586037064 31134165777 31518538194 31586356458 31976311476 32244014088 32730789663 32951199021 33134873486 33897553272 33964544484 34383859848 34409291697 34641004099 34931015262 35362262364 35706315996 36147134712 36722349378 37175711716 37537409124 38106562104 38605546782 38681842329 39159395938 40060744776 40665526551 41512221036 42024717592 42115141944 43399140174 43641052884 43934932028 45319554918 45624737106 45879055596 46574687016 47277807291 47379534687 47964467214 48963132504 49702310229 50846329908 51474062376 51575789772 52396522893 53043393546 53559473994 54220702068 55083524067 55763567574 56306113686 57478459896 57865520232 57908320173 58623237706 58739093907 60091117164 60426073224 60832982808 62268331554 63037076388 63172712916 63952622952 65098710261 65461579326 65902398042 66269746972 67929088968 68437105659 68818583394 69282008198 69862030524 70724524728 71412631992 71946700821 73444698756 74351423432 75074818248 77211093564 77363684658 78318791876 79565090319 81331053102 83024442072 83645351361 84459170529 86798280348 87282105768 87869864056 87934856559 90639109836 91249474212 91758111192 93402497331 94555614582 94759069374 95928934428 98192368989 98853597063 99404620458 101692659816 103151579544 103227875091 103923012297 104793045786 106086787092 107118947988 108441404136 110167048134 111527135148 112612227372 115816640346 116045526987 117246475412 117478187814 120182234328 120821063077 121996579653 124536663108 126074152776 126345425832 130197420522 130923158652 131804796084 132539493944 136874211318 137637166788 138564016396 139724061048 141833421873 143893401642 146889397512 149106930687 154422187128 154727369316 156637583752 159130180638 162662106204 165250572201 167290702722 168918341058 173596560696 173724960519 175869713118 176217281721 181278219672 182498948424 186804994662 189111229164 189518138748 191857868856 195296130783 196384737978 197707194126 198809240916 205311316977 206455750182 207846024594 209586091572 212173574184 214237895976 215376677659 215840102463 220334096268 223054270296 225224454744 231633280692 232091053974 234492950824 234956375628 238695270957 241642126154 243993159306 249073326216 250936054083 260394841044 261846317304 263609592168 263804569677 273748422636 275274333576 277128032792 283666843746 287786803284 294577106967 296560791189 298213861374 309454738632 309683625273 311769036891 318260361276 325324212408 330501144402 334581405444 337836682116 347449921038 348136580961 351739426236 352434563442 362463189231 365989738959 373609989324 378222458328 379036277496 381051045089 390592261566 392769475956 395414388252 397618481832 410622633954 412911500364 415692049188 419172183144 425500265619 430753355318 431680204926 440668192536 447320792061 450333053287 463266561384 464182107948 469912751256 477390541914 483284252308 487986318612 501872108166 520789682088 521174881557 527609139354 528651845163 547496845272 567333687492 575573606568 589154213934 593121582378 596427722748 615933950931 619367250546 623538073782 636520722552 646130032977 647520307389 661002288804 669162810888 675673364232 694899842076 696273161922 703478852472 704869126884 716085812871 724926378462 731979477918 747219978648 752808162249 762102090178 781184523132 785538951912 790828776504 791413709031 821245267908 825823000728 831384098376 851000531238 861506710636 863360409852 889682373567 894641584122 900666106574 928364215896 929050875819 935307110673 954781083828 966568504616 975972637224 1003744216332 1042349763114 1055218278708 1057303690326 1087389567693 1097969216877 1134667374984 1143153135267 1178308427868 1186243164756 1192855445496 1231867901862 1238734501092 1247076147564 1276500796857 1292260065954 1295040614778 1322004577608 1341962376183 1350999159861 1389799684152 1392546323844 1409738253768 1432171625742 1449852756924 1463958955836 1505616324498 1524204180356 1562369046264 1582827418062 1585955535489 1642490535816 1702001062476 1723013421272 1726720819704 1779364747134 1789283168244 1801332213148 1858101751638 1870614221346 1909562167656 1938390098931 1942560922167 2007488432664 2084699526228 2110436557416 2114607380652 2148257438613 2174779135386 2195938433754 2258424486747 2286306270534 2356616855736 2372486329512 2374241127093 2463735803724 2477469002184 2494152295128 2553001593714 2584520131908 2590081229556 2669047120701 2683924752366 2701998319722 2785092647688 2805921332019 2864343251484 2899705513848 2927917911672 3011232648996 3048408360712 3165654836124 3171911070978 3262168703079 3404002124952 3429459405801 3558729494268 3578566336488 3602664426296 3716203503276 3741228442692 3829502390571 3876780197862 3885121844334 4025887128549 4052997479583 4169399052456 4229214761304 4296514877226 4349558270772 4391876867508 4516848973494 4572612541068 4748482254186 4757866606467 4927471607448 4953663586157 5106003187428 5169040263816 5180162459112 5338094241402 5367849504732 5403996639444 5611842664038 5728686502968 5815170296793 6022465297992 6331309672248 6343822141956 6524337406158 6775273460241 6858918811602 7117458988536 7122723381279 7432407006552 7482456885384 7659004781142 7753560395724 7770243688668 8007141362103 8051774257098 8105994959166 8417763996057 8593029754452 8699116541544 8783753735016 9033697946988 9145225082136 9496964508372 9515733212934 9786506109237 9907327172314 10212006374856 10288378217403 10676188482804 10735699009464 10807993278888 11223685328076 11630340593586 12077661385647 12158992438749 12687644283912 13048674812316 13550546920482 13717837623204 14245446762558 14273599819401 14860990758471 15318009562284 15507120791448 15540487377336 16014282724206 16103548514196 16211989918332 16835527992114 17186059508904 17445510890379 18067395893976 18993929016744 19031466425868 19573012218474 19814654344628 20576756434806 21352376965608 21368170143837 22447370656152 23260681187172 24155322771294 24317984877498 25253291988171 26097349624632 27101093840964 27435675246408 28490893525116 28547199638802 29359518327711 29721981516942 30636019124568 30865134652209 32028565448412 32207097028392 32423979836664 33671055984228 34891021780758 36476977316247 38062932851736 39146024436948 39629308689256 41153512869612 42736340287674 44582972275413 46521362374344 48310645542588 48635969754996 50506583976342 52336532671137 54202187681928 56981787050232 57094399277604 58719036655422 59443963033884 61730269304418 64057130896824 67342111968456 69782043561516 72953954632494 78292048873896 82307025739224 85472680575348 88078554983133 89165944550826 92595403956627 96621291085176 97271939509992 101013167952684 104673065342274 109430931948741 114188798555208 117438073310844 118887926067768 123460538608836 133748916826239 139564087123032 145907909264988 157009598013411 170945361150696 176157109966266 178331889101652 185190807913254 202026335905368 209346130684548 218861863897482 234876146621688 246921077217672 267497833652478 277786211869881 291815818529976 314019196026822 328292795846223 352314219932532 356663778203304 370381615826508 401246750478717 418692261369096 437723727794964 534995667304956 555572423739762 628038392053644 656585591692446 704628439865064 740763231653016 802493500957434 875447455589928 1069991334609912 1111144847479524 1203740251436151 1256076784107288 1313171183384892 1604987001914868 2222289694959048 2407480502872302 2626342366769784 3209974003829736 3611220754308453 4814961005744604 7222441508616906 9629922011489208 14444883017233812 28889766034467624
- Sum of all divisors σ(n): 102611998797900480
- Sum of proper divisors (its aliquot sum) s(n): 73722232763432856
- 28889766034467624 is an abundant number, because the sum of its proper divisors (73722232763432856) is greater than itself. Its abundance is 44832466728965232
Bases of 28889766034467624
- Binary: 11001101010001100010110110100100010000011101011001010002
- Hexadecimal: 0x66A316D220EB28
- Base-36: 7WGKFAP9MI0
Squares and roots of 28889766034467624
- 28889766034467624 squared (288897660344676242) is 834618581526279185059985104205376
- 28889766034467624 cubed (288897660344676243) is 24111935548313447958514802693652912599367718746624
-
The
square root of 28889766034467624 is 169969897.4361861053 -
The
cube root of 28889766034467624 is 306841.9082071677
Scales and comparisons
How big is 28889766034467624?- 28,889,766,034,467,624 seconds is equal to 918,605,197 years, 51 weeks, 14 hours, 20 minutes, 24 seconds.
-
To count from 1 to 28,889,766,034,467,624 would take you about two billion, seven hundred fifty-five million, eight hundred fifteen thousand, five hundred ninety-three years!
This is a very rough estimate, based on a speaking rate of half a second every third order of magnitude. If you speak quickly, you could probably say any randomly-chosen number between one and a thousand in around half a second. Very big numbers obviously take longer to say, so we add half a second for every extra x1000. (We do not count involuntary pauses, bathroom breaks or the necessity of sleep in our calculation!)
- A cube with a volume of 28889766034467624 cubic inches would be around 25570.2 feet tall.
Recreational maths with 28889766034467624
- 28889766034467624 backwards is 42676443066798882
- The number of decimal digits it has is: 17
- The sum of 28889766034467624's digits is 90
- More coming soon!
Link to this page
HTML: To link to this page, just copy and paste the link below into your blog, web page or email.
BBCODE: To link to this page in a forum post or comment box, just copy and paste the link code below:
Cite this page
MLA style:
"Number 28889766034467624 - Facts about the integer". Numbermatics.com. 2024. Web. 22 September 2024.
APA style:
Numbermatics. (2024). Number 28889766034467624 - Facts about the integer. Retrieved 22 September 2024, from https://numbermatics.com/n/28889766034467624/
Chicago style:
Numbermatics. 2024. "Number 28889766034467624 - Facts about the integer". https://numbermatics.com/n/28889766034467624/
The information we have on file for 28889766034467624 includes mathematical data and numerical statistics calculated using standard algorithms and methods. We are adding more all the time. If there are any features you would like to see, please contact us. Information provided for educational use, intellectual curiosity and fun!
Keywords: Divisors of 28889766034467624, math, Factors of 28889766034467624, curriculum, school, college, exams, university, Prime factorization of 28889766034467624, STEM, science, technology, engineering, physics, economics, calculator, twenty-eight quadrillion, eight hundred eighty-nine trillion, seven hundred sixty-six billion, thirty-four million, four hundred sixty-seven thousand, six hundred twenty-four.