Yes, 7 is a prime number. Its only factors are 1 and 7.
A number is prime if no smaller prime up to its square root divides it. The square root of 7 is about 2.65, so it is enough to test the primes 2.
| Divide by | Remainder | Divides evenly? |
|---|---|---|
| 2 | 1 | No |
None of them divides 7 evenly, so 7 is prime.
| Number | Prime? |
|---|---|
| 3 | Yes |
| 4 | No, 2 × 2 |
| 5 | Yes |
| 6 | No, 2 × 3 |
| 8 | No, 2 × 2 × 2 |
| 9 | No, 3 × 3 |
| 10 | No, 2 × 5 |
| 11 | Yes |
More about 7: factors of 7 · 7 squared · square root of 7 · 7 in binary · 7 in Roman numerals.
Another number? Use the prime number checker for any value, or see the list of prime numbers.