81921

Names of 81921

• Cardinal: 81921 can be written as Eighty-one thousand, nine hundred twenty-one.

Scientific notation

• Scientific notation: 8.1921 × 10⁴

Factors of 81921

• Number of distinct prime factors ω(n): 4
• Total number of prime factors Ω(n): 4
• Sum of prime factors: 140

Divisors of 81921

• Number of divisors d(n): 16
• Complete list of divisors:
  1 3 7 21 47 83 141 249 329 581 987 1743 3901 11703 27307 81921
• Sum of all divisors σ(n): 129024
• Sum of proper divisors (its aliquot sum) s(n): 47103
• 81921 is a deficient number, because the sum of its proper divisors (47103) is less than itself. Its deficiency is 34818

Bases of 81921

• Binary: 10100000000000001₂
• Hexadecimal: 0x14001
• Base-36: 1R7L

Squares and roots of 81921

• 81921 squared (81921²) is 6711050241
• 81921 cubed (81921³) is 549775946792961
• The square root of 81921 is 286.2184480425
• The cube root of 81921 is 43.4308585847

Scales and comparisons

• 81,921 seconds is equal to 22 hours, 45 minutes, 21 seconds.
• To count from 1 to 81,921 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 81921 cubic inches would be around 3.6 feet tall.

Recreational maths with 81921

• 81921 backwards is 12918
• 81921 is a Harshad number.
• The number of decimal digits it has is: 5
• The sum of 81921's digits is 21
• More coming soon!