No, 285 is not a prime number. It is a composite number: it ends in 5, so it is divisible by 5.
285 has divisors other than 1 and itself. The smallest is 3: 285 ÷ 3 = 95.
Prime factorization: 285 = 3 × 5 × 19.
| Number | Prime? |
|---|---|
| 281 | Yes |
| 282 | No, 2 × 3 × 47 |
| 283 | Yes |
| 284 | No, 2 × 2 × 71 |
| 286 | No, 2 × 11 × 13 |
| 287 | No, 7 × 41 |
| 288 | No, 2 × 2 × 2 × 2 × 2 × 3 × 3 |
| 289 | No, 17 × 17 |
Another number? Use the prime number checker for any value, or see the list of prime numbers.