21391

Names of 21391

• Cardinal: 21391 can be written as Twenty-one thousand, three hundred ninety-one.

Scientific notation

• Scientific notation: 2.1391 × 10⁴

Factors of 21391

• Number of distinct prime factors ω(n): 1
• Total number of prime factors Ω(n): 1
• Sum of prime factors: 21391

Divisors of 21391

• Number of divisors d(n): 2
• Complete list of divisors:
  1 21391
• Sum of all divisors σ(n): 21392
• Sum of proper divisors (its aliquot sum) s(n): 1
• 21391 is a deficient number, because the sum of its proper divisors (1) is less than itself. Its deficiency is 21390

Bases of 21391

• Binary: 101001110001111₂
• Hexadecimal: 0x538F
• Base-36: GI7

Squares and roots of 21391

• 21391 squared (21391²) is 457574881
• 21391 cubed (21391³) is 9787984279471
• The square root of 21391 is 146.2566237817
• The cube root of 21391 is 27.7594183867

Scales and comparisons

• 21,391 seconds is equal to 5 hours, 56 minutes, 31 seconds.
• To count from 1 to 21,391 would take you about five 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 21391 cubic inches would be around 2.3 feet tall.

Recreational maths with 21391

• 21391 backwards is 19312
• The number of decimal digits it has is: 5
• The sum of 21391's digits is 16
• More coming soon!