Factors of 28

The factors of 28 are 1, 2, 4, 7, 14, 28. It has 6 factors.

Factors of 28

Pick any whole number from 1 to 10,000.

28 = 2^{2} \times 7

How to work it out

1
A factor of 28 is a whole number that divides it with nothing left over. You only need to test the numbers up to √28 ≈ 5.29; every one that divides gives a pair.
2
The factor pairs are listed in the table below. Together they give 6 factors.
3
Prime factorisation: keep dividing by the smallest prime that fits.
$28 = 2^{2} \times 7$
4
Add all the factors: 1 + 2 + 4 + 7 + 14 + 28 = 56. Without 28 itself that is 28, so 28 is a perfect number.

LaTeX source of the formulas on this page

\[ 28 = 2^{2} \times 7 \]

What are the factors of 28?

The factors of 28 are 1, 2, 4, 7, 14, 28. It has 6 factors.

What are the prime factors of 28?

2, 7. As a product: $2^{2}$ × 7.

How many factors does 28 have?

28 has 6 factors (3 factor pairs).

What is the sum of the factors of 28?

56.

Is 28 a prime number?

No. It is divisible by 2, so 28 = 2 × 14.