Calculators

Math

Factors

20 is a round number that forms the basis of many counting systems (fingers plus toes). It has 6 factors and equals 4 × 5.

All Factors

The factors of 20 are:  1, 2, 4, 5, 10, 20

The prime factorization is: 20 = 2 x 2 x 5

Factoring of 20 Using Trial Division

Find the Factors of 20 :

• Calculate the square root of 20 which is 4.4721, and round it down to the closest whole number, 4, and use it in the next step.
• Test the integer values 1 through 4 for division into 20 where the remainder equals 0.
• We find 6 factors where the remainder of division is 0 and they are: 1, 2, 4, 5, 10, 20.

Factor Pairs

1 × 20 = 20
2 × 10 = 20
4 × 5 = 20

The factor pairs (multiples) that equal 20 when multiplied together are: (1 and 20), (2 and 10), (4 and 5), which we found by matching up all factors of 20 which are: 1, 2, 4, 5, 10, 20.

Is 20 Prime or Composite?

20 is a composite number. Since it has more than two factors, we know that 20 is not prime, it is composite. Prime numbers only have two factors. They are evenly divisible by only 1 and itself.