Factors of 18

The factors of 18 are 1, 2, 3, 6, 9, 18. It has 6 factors.

Factors of 18

Pick any whole number from 1 to 10,000.

18 = 2 \times 3^{2}

How to work it out

1
A factor of 18 is a whole number that divides it with nothing left over. You only need to test the numbers up to √18 ≈ 4.24; 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.
$18 = 2 \times 3^{2}$
4
Add all the factors: 1 + 2 + 3 + 6 + 9 + 18 = 39. Without 18 itself that is 21, so 18 is an abundant number.

LaTeX source of the formulas on this page

\[ 18 = 2 \times 3^{2} \]

What are the factors of 18?

The factors of 18 are 1, 2, 3, 6, 9, 18. It has 6 factors.

What are the prime factors of 18?

2, 3. As a product: 2 × $3^{2}$ .

How many factors does 18 have?

18 has 6 factors (3 factor pairs).

What is the sum of the factors of 18?

39.

Is 18 a prime number?

No. It is divisible by 2, so 18 = 2 × 9.