Factors of 261

3, 29. As a product: 3^2 × 29.

The factors of 261 are 1, 3, 9, 29, 87, 261. It has 6 factors.

Factors of 261

Pick any whole number from 1 to 10,000.

261 = 3^{2} \times 29

How to work it out

1
A factor of 261 is a whole number that divides it with nothing left over. You only need to test the numbers up to √261 ≈ 16.16; 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.
$261 = 3^{2} \times 29$
4
Add all the factors: 1 + 3 + 9 + 29 + 87 + 261 = 390. Without 261 itself that is 129, so 261 is a deficient number.

LaTeX source of the formulas on this page

\[ 261 = 3^{2} \times 29 \]

What are the factors of 261?

The factors of 261 are 1, 3, 9, 29, 87, 261. It has 6 factors.

What are the prime factors of 261?

3, 29. As a product: $3^{2}$ × 29.

How many factors does 261 have?

261 has 6 factors (3 factor pairs).

What is the sum of the factors of 261?

390.

Is 261 a prime number?

No. It is divisible by 3, so 261 = 3 × 87.