Yes, 109 is a prime number. Its only factors are 1 and 109.
A number is prime if no smaller prime up to its square root divides it. The square root of 109 is about 10.44, so it is enough to test the primes 2, 3, 5 and 7.
| Divide by | Remainder | Divides evenly? |
|---|---|---|
| 2 | 1 | No |
| 3 | 1 | No |
| 5 | 4 | No |
| 7 | 4 | No |
None of them divides 109 evenly, so 109 is prime.
| Number | Prime? |
|---|---|
| 105 | No, 3 × 5 × 7 |
| 106 | No, 2 × 53 |
| 107 | Yes |
| 108 | No, 2 × 2 × 3 × 3 × 3 |
| 110 | No, 2 × 5 × 11 |
| 111 | No, 3 × 37 |
| 112 | No, 2 × 2 × 2 × 2 × 7 |
| 113 | Yes |
More about 109: factors of 109 · 109 squared · square root of 109 · 109 in binary · 109 in Roman numerals.
Another number? Use the prime number checker for any value, or see the list of prime numbers.