Factors of 561
The factors of 561 are 1, 3, 11, 17, 33, 51, 187, 561. It has 8 factors.
Factors of 561
Pick any whole number from 1 to 10,000.
How to work it out
- 1
A factor of 561 is a whole number that divides it with nothing left over. You only need to test the numbers up to √561 ≈ 23.69; every one that divides gives a pair.
- 2
The factor pairs are listed in the table below. Together they give 8 factors.
- 3
Prime factorisation: keep dividing by the smallest prime that fits.
- 4
Add all the factors: 1 + 3 + 11 + 17 + 33 + 51 + 187 + 561 = 864. Without 561 itself that is 303, so 561 is a deficient number.
LaTeX source of the formulas on this page
\[ 561 = 3 \times 11 \times 17 \]
Factor pairs of 561
| Factor | Pairs with | Product |
|---|---|---|
| 1 | 561 | 1 × 561 = 561 |
| 3 | 187 | 3 × 187 = 561 |
| 11 | 51 | 11 × 51 = 561 |
| 17 | 33 | 17 × 33 = 561 |
Questions
What are the factors of 561?
The factors of 561 are 1, 3, 11, 17, 33, 51, 187, 561. It has 8 factors.
What are the prime factors of 561?
3, 11, 17. As a product: 3 × 11 × 17.
How many factors does 561 have?
561 has 8 factors (4 factor pairs).
What is the sum of the factors of 561?
864.
Is 561 a prime number?
No. It is divisible by 3, so 561 = 3 × 187.