Factors of 3991

The factors of 3991 are 1, 13, 307, 3991. It has 4 factors.

Factors of 3991

Pick any whole number from 1 to 10,000.

3991 = 13 \times 307

How to work it out

1
A factor of 3991 is a whole number that divides it with nothing left over. You only need to test the numbers up to √3991 ≈ 63.17; every one that divides gives a pair.
2
The factor pairs are listed in the table below. Together they give 4 factors.
3
Prime factorisation: keep dividing by the smallest prime that fits.
$3991 = 13 \times 307$
4
Add all the factors: 1 + 13 + 307 + 3991 = 4312. Without 3991 itself that is 321, so 3991 is a deficient number.

LaTeX source of the formulas on this page

\[ 3991 = 13 \times 307 \]

Factor	Pairs with	Product
1	3991	1 × 3991 = 3991
13	307	13 × 307 = 3991

What are the factors of 3991?

The factors of 3991 are 1, 13, 307, 3991. It has 4 factors.

What are the prime factors of 3991?

13, 307. As a product: 13 × 307.

How many factors does 3991 have?

3991 has 4 factors (2 factor pairs).

What is the sum of the factors of 3991?

4312.

Is 3991 a prime number?

No. It is divisible by 13, so 3991 = 13 × 307.