No, 78 is not a prime number. It is a composite number: it is even, so it is divisible by 2.
78 has divisors other than 1 and itself. The smallest is 2: 78 ÷ 2 = 39.
Prime factorization: 78 = 2 × 3 × 13.
| Number | Prime? |
|---|---|
| 74 | No, 2 × 37 |
| 75 | No, 3 × 5 × 5 |
| 76 | No, 2 × 2 × 19 |
| 77 | No, 7 × 11 |
| 79 | Yes |
| 80 | No, 2 × 2 × 2 × 2 × 5 |
| 81 | No, 3 × 3 × 3 × 3 |
| 82 | No, 2 × 41 |
More about 78: factors of 78 · 78 squared · square root of 78 · 78 in binary · 78 in Roman numerals.
Another number? Use the prime number checker for any value, or see the list of prime numbers.