| Next prime | 41 |
| Previous prime | 31 |
| Octal | (45)8 |
| Hexadecimal | (25)16 |
| Prime gap | 4 |
| 6th Prime triplet (the smallest number) | The others are 41 and 43 . |
| 5th Cousin prime (the small number) | The big number is 41 . |
| 8th Sexy prime (the small number) | The big number is 43 . |
| 5th Prime of the Form 3n+1 | 52 + 3 * 22 |
| 5th Prime of the Form 4n+1 | 12 + 62 |
| 4th Emirp (reversible prime) | |
| 8th Left-truncatable prime | |
| 8th Right-truncatable prime | |
| 6th Two-sided prime |