Yes, 67 is a prime number. Its only factors are 1 and 67.
A number is prime if no smaller prime up to its square root divides it. The square root of 67 is about 8.19, so it is enough to test the primes 2, 3, 5 and 7.
| Divide by | Remainder | Divides evenly? |
|---|---|---|
| 2 | 1 | No |
| 3 | 1 | No |
| 5 | 2 | No |
| 7 | 4 | No |
None of them divides 67 evenly, so 67 is prime.
| Number | Prime? |
|---|---|
| 63 | No, 3 × 3 × 7 |
| 64 | No, 2 × 2 × 2 × 2 × 2 × 2 |
| 65 | No, 5 × 13 |
| 66 | No, 2 × 3 × 11 |
| 68 | No, 2 × 2 × 17 |
| 69 | No, 3 × 23 |
| 70 | No, 2 × 5 × 7 |
| 71 | Yes |
More about 67: factors of 67 · 67 squared · square root of 67 · 67 in binary · 67 in Roman numerals.
Another number? Use the prime number checker for any value, or see the list of prime numbers.