20 is an even composite number composed of two prime numbers multiplied together.

20 is an even composite number. It is composed of two distinct prime numbers multiplied together. It has a total of six divisors.

Prime factorization of 20:

22 × 5

(2 × 2 × 5)

See below for interesting mathematical facts about the number 20 from the Numbermatics database.

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Names Factors Divisors Scales Roots Fun

Names of 20

  • Cardinal: 20 can be written as Twenty.

Scientific notation

  • Scientific notation: 2 × 101

Factors of 20

  • Number of distinct prime factors ω(n): 2
  • Total number of prime factors Ω(n): 3
  • Sum of prime factors: 7

Divisors of 20

  • Number of divisors d(n): 6
  • Complete list of divisors:
    1 2 4 5 10 20
  • Sum of all divisors σ(n): 42
  • Sum of proper divisors (its aliquot sum) s(n): 22
  • 20 is an abundant number, because the sum of its proper divisors (22) is greater than itself. Its abundance is 2

Bases of 20

  • Binary: 10100 2
  • Hexadecimal: 0x14

Squares and roots of 20

  • 20 squared (202) is 400
  • 20 cubed (203) is 8000
  • The square root of 20 is 4.4721359549
  • The cube root of 20 is 2.7144176165

Scales and comparisons

How big is 20?
  • To count from 1 to 20 would take you about ten 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 20 cubic inches would be around 0.2 feet tall.

Recreational maths with 20

  • 20 backwards is 02
  • 20 is a Harshad number.
  • The number of decimal digits it has is: 2
  • The sum of 20's digits is 2
  • More coming soon!

The information we have on file for 20 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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