Yes, 101 is a prime number. Its only factors are 1 and 101.
A number is prime if no smaller prime up to its square root divides it. The square root of 101 is about 10.05, so it is enough to test the primes 2, 3, 5 and 7.
| Divide by | Remainder | Divides evenly? |
|---|---|---|
| 2 | 1 | No |
| 3 | 2 | No |
| 5 | 1 | No |
| 7 | 3 | No |
None of them divides 101 evenly, so 101 is prime.
| Number | Prime? |
|---|---|
| 97 | Yes |
| 98 | No, 2 × 7 × 7 |
| 99 | No, 3 × 3 × 11 |
| 100 | No, 2 × 2 × 5 × 5 |
| 102 | No, 2 × 3 × 17 |
| 103 | Yes |
| 104 | No, 2 × 2 × 2 × 13 |
| 105 | No, 3 × 5 × 7 |
More about 101: factors of 101 · 101 squared · square root of 101 · 101 in binary · 101 in Roman numerals.
Another number? Use the prime number checker for any value, or see the list of prime numbers.