No, 128 is not a prime number. It is a composite number: it is even, so it is divisible by 2.
128 has divisors other than 1 and itself. The smallest is 2: 128 ÷ 2 = 64.
Prime factorization: 128 = 2 × 2 × 2 × 2 × 2 × 2 × 2 = 2⁷.
| Number | Prime? |
|---|---|
| 124 | No, 2 × 2 × 31 |
| 125 | No, 5 × 5 × 5 |
| 126 | No, 2 × 3 × 3 × 7 |
| 127 | Yes |
| 129 | No, 3 × 43 |
| 130 | No, 2 × 5 × 13 |
| 131 | Yes |
| 132 | No, 2 × 2 × 3 × 11 |
More about 128: factors of 128 · 128 squared · square root of 128 · 128 in binary · 128 in Roman numerals.
Another number? Use the prime number checker for any value, or see the list of prime numbers.