No, 9 is not a prime number. It is a composite number: its digits add up to 9, which is divisible by 3, so 9 is divisible by 3.
9 has divisors other than 1 and itself. The smallest is 3: 9 ÷ 3 = 3.
Prime factorization: 9 = 3 × 3 = 3².
| Number | Prime? |
|---|---|
| 5 | Yes |
| 6 | No, 2 × 3 |
| 7 | Yes |
| 8 | No, 2 × 2 × 2 |
| 10 | No, 2 × 5 |
| 11 | Yes |
| 12 | No, 2 × 2 × 3 |
| 13 | Yes |
More about 9: factors of 9 · 9 squared · square root of 9 · 9 in binary · 9 in Roman numerals.
Another number? Use the prime number checker for any value, or see the list of prime numbers.