Yes, 163 is a prime number. Its only factors are 1 and 163.
A number is prime if no smaller prime up to its square root divides it. The square root of 163 is about 12.77, so it is enough to test the primes 2, 3, 5, 7 and 11.
| Divide by | Remainder | Divides evenly? |
|---|---|---|
| 2 | 1 | No |
| 3 | 1 | No |
| 5 | 3 | No |
| 7 | 2 | No |
| 11 | 9 | No |
None of them divides 163 evenly, so 163 is prime.
| Number | Prime? |
|---|---|
| 159 | No, 3 × 53 |
| 160 | No, 2 × 2 × 2 × 2 × 2 × 5 |
| 161 | No, 7 × 23 |
| 162 | No, 2 × 3 × 3 × 3 × 3 |
| 164 | No, 2 × 2 × 41 |
| 165 | No, 3 × 5 × 11 |
| 166 | No, 2 × 83 |
| 167 | Yes |
More about 163: factors of 163 · square root of 163 · 163 in binary.
Another number? Use the prime number checker for any value, or see the list of prime numbers.