No, 261 is not a prime number. It is a composite number: its digits add up to 9, which is divisible by 3, so 261 is divisible by 3.
261 has divisors other than 1 and itself. The smallest is 3: 261 ÷ 3 = 87.
Prime factorization: 261 = 3 × 3 × 29 = 3² × 29.
| Number | Prime? |
|---|---|
| 257 | Yes |
| 258 | No, 2 × 3 × 43 |
| 259 | No, 7 × 37 |
| 260 | No, 2 × 2 × 5 × 13 |
| 262 | No, 2 × 131 |
| 263 | Yes |
| 264 | No, 2 × 2 × 2 × 3 × 11 |
| 265 | No, 5 × 53 |
Another number? Use the prime number checker for any value, or see the list of prime numbers.