No, 321 is not a prime number. It is a composite number: its digits add up to 6, which is divisible by 3, so 321 is divisible by 3.
321 has divisors other than 1 and itself. The smallest is 3: 321 ÷ 3 = 107.
Prime factorization: 321 = 3 × 107.
| Number | Prime? |
|---|---|
| 317 | Yes |
| 318 | No, 2 × 3 × 53 |
| 319 | No, 11 × 29 |
| 320 | No, 2 × 2 × 2 × 2 × 2 × 2 × 5 |
| 322 | No, 2 × 7 × 23 |
| 323 | No, 17 × 19 |
| 324 | No, 2 × 2 × 3 × 3 × 3 × 3 |
| 325 | No, 5 × 5 × 13 |
Another number? Use the prime number checker for any value, or see the list of prime numbers.