Yes, 487 is a prime number. Its only factors are 1 and 487.
A number is prime if no smaller prime up to its square root divides it. The square root of 487 is about 22.07, so it is enough to test the primes 2, 3, 5, 7, 11, 13, 17 and 19.
| Divide by | Remainder | Divides evenly? |
|---|---|---|
| 2 | 1 | No |
| 3 | 1 | No |
| 5 | 2 | No |
| 7 | 4 | No |
| 11 | 3 | No |
| 13 | 6 | No |
| 17 | 11 | No |
| 19 | 12 | No |
None of them divides 487 evenly, so 487 is prime.
| Number | Prime? |
|---|---|
| 483 | No, 3 × 7 × 23 |
| 484 | No, 2 × 2 × 11 × 11 |
| 485 | No, 5 × 97 |
| 486 | No, 2 × 3 × 3 × 3 × 3 × 3 |
| 488 | No, 2 × 2 × 2 × 61 |
| 489 | No, 3 × 163 |
| 490 | No, 2 × 5 × 7 × 7 |
| 491 | Yes |
Another number? Use the prime number checker for any value, or see the list of prime numbers.