Yes, 17 is a prime number. Its only factors are 1 and 17.
A number is prime if no smaller prime up to its square root divides it. The square root of 17 is about 4.12, so it is enough to test the primes 2 and 3.
| Divide by | Remainder | Divides evenly? |
|---|---|---|
| 2 | 1 | No |
| 3 | 2 | No |
None of them divides 17 evenly, so 17 is prime.
| Number | Prime? |
|---|---|
| 13 | Yes |
| 14 | No, 2 × 7 |
| 15 | No, 3 × 5 |
| 16 | No, 2 × 2 × 2 × 2 |
| 18 | No, 2 × 3 × 3 |
| 19 | Yes |
| 20 | No, 2 × 2 × 5 |
| 21 | No, 3 × 7 |
More about 17: factors of 17 · 17 squared · square root of 17 · 17 in binary · 17 in Roman numerals.
Another number? Use the prime number checker for any value, or see the list of prime numbers.