Factors of 391
The factors of 391 are 1, 17, 23, 391. It has 4 factors.
Factors of 391
Pick any whole number from 1 to 10,000.
How to work it out
- 1
A factor of 391 is a whole number that divides it with nothing left over. You only need to test the numbers up to ā391 ā 19.77; 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.
- 4
Add all the factors: 1 + 17 + 23 + 391 = 432. Without 391 itself that is 41, so 391 is a deficient number.
LaTeX source of the formulas on this page
\[ 391 = 17 \times 23 \]
Factor pairs of 391
| Factor | Pairs with | Product |
|---|---|---|
| 1 | 391 | 1 Ć 391 = 391 |
| 17 | 23 | 17 Ć 23 = 391 |
Questions
What are the factors of 391?
The factors of 391 are 1, 17, 23, 391. It has 4 factors.
What are the prime factors of 391?
17, 23. As a product: 17 Ć 23.
How many factors does 391 have?
391 has 4 factors (2 factor pairs).
What is the sum of the factors of 391?
432.
Is 391 a prime number?
No. It is divisible by 17, so 391 = 17 Ć 23.