21 Ternary to Octal
21 ternary = 7 octal
21 written in octal is 7, the number 7 in everyday decimal.
21 ternary = 7 octal
How to convert 21 to octal
Step 1: Ternary to decimal
Multiply each digit by 3 to the power of its position (0 on the right), then add:
| Digit | Place value | Digit × place |
|---|---|---|
2 | 31 = 3 | 6 |
1 | 30 = 1 | 1 |
6 + 1 = 7
Step 2: Decimal to octal
Divide by 8 repeatedly and keep the remainders. Reading the remainders from the last one to the first gives the octal digits:
| Division | Quotient | Remainder (digit) |
|---|---|---|
| 7 ÷ 8 | 0 | 7 |
Result: 7 = 7 in octal.
21 (ternary) in other systems
| Binary | 111 |
| Decimal | 7 |
| Roman numerals | VII |
| Hexadecimal | 7 |
| Duodecimal | 7 |
| Base 36 | 7 |
| Vigesimal | 7 |
| Quaternary | 13 |
| Quinary | 12 |
| Senary | 11 |
Nearby ternary to octal conversions
| 2 to octal | 2 |
| 10 to octal | 3 |
| 11 to octal | 4 |
| 12 to octal | 5 |
| 20 to octal | 6 |
| 22 to octal | 10 |
| 100 to octal | 11 |
| 101 to octal | 12 |
| 102 to octal | 13 |
| 110 to octal | 14 |
About the number 7
- 7 is an odd number.
- 7 is a prime number.
- Written in binary it needs 3 bits, so it fits in one byte.
Reverse conversion
Frequently asked questions
What is 21 in octal?
21 in ternary is 7 in octal (the number 7 in decimal).