31 is a prime number. Like all primes greater than two, it is odd and has no factors apart from itself and one.

31 is a prime number. Like all primes (except two), it is an odd number.

Prime factorization of 31:


See below for interesting mathematical facts about the number 31 from the Numbermatics database.

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Names Factors Divisors Scales Roots Fun

Names of 31

  • Cardinal: 31 can be written as Thirty-one.

Scientific notation

  • Scientific notation: 3.1 × 101

Factors of 31

  • Number of distinct prime factors ω(n): 1
  • Total number of prime factors Ω(n): 1
  • Sum of prime factors: 31

Divisors of 31

  • Number of divisors d(n): 2
  • Complete list of divisors:
    1 31
  • Sum of all divisors σ(n): 32
  • Sum of proper divisors (its aliquot sum) s(n): 1
  • 31 is a deficient number, because the sum of its proper divisors (1) is less than itself. Its deficiency is 30

Bases of 31

  • Binary: 11111 2
  • Hexadecimal: 0x1F
  • Base-36: V

Squares and roots of 31

  • 31 squared (312) is 961
  • 31 cubed (313) is 29791
  • The square root of 31 is 5.5677643629
  • The cube root of 31 is 3.1413806523

Scales and comparisons

How big is 31?
  • To count from 1 to 31 would take you about fifteen seconds.

    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.

    Note: we do not count involuntary pauses, bathroom breaks or the necessity of sleep in our calculation!

  • A cube with a volume of 31 cubic inches would be around 0.3 feet tall.

Recreational maths with 31

  • 31 backwards is 13
  • The number of decimal digits it has is: 2
  • The sum of 31's digits is 4
  • More coming soon!

The information we have on file for 31 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!

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