21905

Names of 21905

• Cardinal: 21905 can be written as Twenty-one thousand, nine hundred five.

Scientific notation

• Scientific notation: 2.1905 × 10⁴

Factors of 21905

• Number of distinct prime factors ω(n): 3
• Total number of prime factors Ω(n): 3
• Sum of prime factors: 355

Divisors of 21905

• Number of divisors d(n): 8
• Complete list of divisors:
  1 5 13 65 337 1685 4381 21905
• Sum of all divisors σ(n): 28392
• Sum of proper divisors (its aliquot sum) s(n): 6487
• 21905 is a deficient number, because the sum of its proper divisors (6487) is less than itself. Its deficiency is 15418

Bases of 21905

• Binary: 101010110010001₂
• Hexadecimal: 0x5591
• Base-36: GWH

Squares and roots of 21905

• 21905 squared (21905²) is 479829025
• 21905 cubed (21905³) is 10510654792625
• The square root of 21905 is 148.0033783399
• The cube root of 21905 is 27.9800027283

Scales and comparisons

• 21,905 seconds is equal to 6 hours, 5 minutes, 5 seconds.
• To count from 1 to 21,905 would take you about six 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 21905 cubic inches would be around 2.3 feet tall.

Recreational maths with 21905

• 21905 backwards is 50912
• The number of decimal digits it has is: 5
• The sum of 21905's digits is 17
• More coming soon!