Yes, 2 is a prime number. Its only factors are 1 and 2.
A number is prime if no smaller prime up to its square root divides it. The square root of 2 is about 1.41, so it is enough to test no divisors at all.
None of them divides 2 evenly, so 2 is prime.
| Number | Prime? |
|---|---|
| 1 | No (neither) |
| 3 | Yes |
| 4 | No, 2 × 2 |
| 5 | Yes |
| 6 | No, 2 × 3 |
More about 2: factors of 2 · 2 squared · square root of 2 · 2 in binary · 2 in Roman numerals.
Another number? Use the prime number checker for any value, or see the list of prime numbers.