No, 4 is not a prime number. It is a composite number: it is even, so it is divisible by 2.
4 has divisors other than 1 and itself. The smallest is 2: 4 ÷ 2 = 2.
Prime factorization: 4 = 2 × 2 = 2².
| Number | Prime? |
|---|---|
| 1 | No (neither) |
| 2 | Yes |
| 3 | Yes |
| 5 | Yes |
| 6 | No, 2 × 3 |
| 7 | Yes |
| 8 | No, 2 × 2 × 2 |
More about 4: factors of 4 · 4 squared · square root of 4 · 4 in binary · 4 in Roman numerals.
Another number? Use the prime number checker for any value, or see the list of prime numbers.