Divisors of the Positive Integer 21
1, 3, 7, 21Sum of all the Divisors of 21, including itself
32Sum of the Proper Divisors of 21
11Properties of the number 21
The integer 21 is an odd number.The integer 21 is a Composite number.
11 is less than 21, so 21 is a deficient number.
The number 21 as a Roman Numeral
XXIThe number 21 in various Numeral Systems
| Base | Representation |
|---|---|
| 2: | 10101 |
| 3: | 210 |
| 4: | 111 |
| 5: | 41 |
| 6: | 33 |
| 7: | 30 |
| 8: | 25 |
| 9: | 23 |
| 10: | 21 |
| 11: | 1A |
| 12: | 19 |
| 13: | 18 |
| 14: | 17 |
| 15: | 16 |
| 16: | 15 |
| 17: | 14 |
| 18: | 13 |
| 19: | 12 |
| 20: | 11 |
| 21: | 10 |
| 22: | L |
| 23: | L |
| 24: | L |
| 25: | L |
| 26: | L |
| 27: | L |
| 28: | L |
| 29: | L |
| 30: | L |
| 31: | L |
| 32: | L |
| 33: | L |
| 34: | L |
| 35: | L |
| 36: | L |