No, 171 is not a prime number. It is a composite number: its digits add up to 9, which is divisible by 3, so 171 is divisible by 3.
171 has divisors other than 1 and itself. The smallest is 3: 171 ÷ 3 = 57.
Prime factorization: 171 = 3 × 3 × 19 = 3² × 19.
| Number | Prime? |
|---|---|
| 167 | Yes |
| 168 | No, 2 × 2 × 2 × 3 × 7 |
| 169 | No, 13 × 13 |
| 170 | No, 2 × 5 × 17 |
| 172 | No, 2 × 2 × 43 |
| 173 | Yes |
| 174 | No, 2 × 3 × 29 |
| 175 | No, 5 × 5 × 7 |
More about 171: factors of 171 · square root of 171 · 171 in binary.
Another number? Use the prime number checker for any value, or see the list of prime numbers.