Factors of 21 in pairs

Factors are pairs of numbers which, if multiplied together, give the original number.

The number 21 is a composite number. So, 21 has more than one factor pair.

These are all the factor pairs of 21:

• 1,21
• 3,7

Here is how to find the factor pairs for the number 21:

• 21 divided by 1 is 21. So, (1, 21) is a factor pair of 21
• 21 divided by 3 is 7. So, (3, 7) is a factor pair of 21

Factor pairs of 21 that ads up to a number:

• The factors of 21 that adds up to 22 are 1 and 21
• The factors of 21 that adds up to 24 are 3 and 7

Note 1: if we change the order of all pairs above, we can double the number of pairs. We choose not to show them.
Note 2: do not confuse these pairs with prime factors. See below some info:

The factorization or decomposition of 21 is 3•7.

The prime factors of 21 are 3 and 7. It is the list of the integer's prime factors.