No, 423 is not a prime number. It is a composite number: its digits add up to 9, which is divisible by 3, so 423 is divisible by 3.
423 has divisors other than 1 and itself. The smallest is 3: 423 ÷ 3 = 141.
Prime factorization: 423 = 3 × 3 × 47 = 3² × 47.
| Number | Prime? |
|---|---|
| 419 | Yes |
| 420 | No, 2 × 2 × 3 × 5 × 7 |
| 421 | Yes |
| 422 | No, 2 × 211 |
| 424 | No, 2 × 2 × 2 × 53 |
| 425 | No, 5 × 5 × 17 |
| 426 | No, 2 × 3 × 71 |
| 427 | No, 7 × 61 |
Another number? Use the prime number checker for any value, or see the list of prime numbers.