Factors of 1221
The factors of 1221 are 1, 3, 11, 33, 37, 111, 407, 1221. It has 8 factors.
Pick any whole number from 1 to 10,000.
How to work it out
- 1
A factor of 1221 is a whole number that divides it with nothing left over. You only need to test the numbers up to √1221 ≈ 34.94; 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 + 33 + 37 + 111 + 407 + 1221 = 1824. Without 1221 itself that is 603, so 1221 is a deficient number.
LaTeX source of the formulas on this page
\[ 1221 = 3 \times 11 \times 37 \]
Factor pairs of 1221
| Factor | Pairs with | Product |
|---|---|---|
| 1 | 1221 | 1 × 1221 = 1221 |
| 3 | 407 | 3 × 407 = 1221 |
| 11 | 111 | 11 × 111 = 1221 |
| 33 | 37 | 33 × 37 = 1221 |
Questions
What are the factors of 1221?
The factors of 1221 are 1, 3, 11, 33, 37, 111, 407, 1221. It has 8 factors.
What are the prime factors of 1221?
3, 11, 37. As a product: 3 × 11 × 37.
How many factors does 1221 have?
1221 has 8 factors (4 factor pairs).
What is the sum of the factors of 1221?
1824.
Is 1221 a prime number?
No. It is divisible by 3, so 1221 = 3 × 407.