81920

Names of 81920

• Cardinal: 81920 can be written as Eighty-one thousand, nine hundred twenty.

Scientific notation

• Scientific notation: 8.192 × 10⁴

Factors of 81920

• Number of distinct prime factors ω(n): 2
• Total number of prime factors Ω(n): 15
• Sum of prime factors: 7

Divisors of 81920

• Number of divisors d(n): 30
• Complete list of divisors:
  1 2 4 5 8 10 16 20 32 40 64 80 128 160 256 320 512 640 1024 1280 2048 2560 4096 5120 8192 10240 16384 20480 40960 81920
• Sum of all divisors σ(n): 196602
• Sum of proper divisors (its aliquot sum) s(n): 114682
• 81920 is an abundant number, because the sum of its proper divisors (114682) is greater than itself. Its abundance is 32762

Bases of 81920

• Binary: 10100000000000000₂
• Hexadecimal: 0x14000
• Base-36: 1R7K

Squares and roots of 81920

• 81920 squared (81920²) is 6710886400
• 81920 cubed (81920³) is 549755813888000
• The square root of 81920 is 286.2167011203
• The cube root of 81920 is 43.4306818655

Scales and comparisons

• 81,920 seconds is equal to 22 hours, 45 minutes, 20 seconds.
• To count from 1 to 81,920 would take you about twenty-two hours.

  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 81920 cubic inches would be around 3.6 feet tall.

Recreational maths with 81920

• 81920 backwards is 02918
• 81920 is a Harshad number.
• The number of decimal digits it has is: 5
• The sum of 81920's digits is 20
• More coming soon!