| Next prime | 29 |
| Previous prime | 19 |
| Octal | (27)8 |
| Hexadecimal | (17)16 |
| Prime gap | 6 |
| 6th Sexy prime (the small number) | The big number is 29 . |
| 5th Prime of the Form 4n+3 | |
| 5th Factorial prime | 4! - 1 |
| 5th Sophie Germain prime | |
| 4th Safe prime | |
| 7th Left-truncatable prime | |
| 5th Right-truncatable prime | |
| 5th Two-sided prime |