| Numeral systems by culture | |
|---|---|
| Hindu-Arabic numerals | |
| Western Arabic (Hindu numerals) Eastern Arabic Indian family Tamil |
Burmese Khmer Lao Mongolian Thai |
| East Asian numerals | |
| Chinese Japanese Suzhou |
Korean Vietnamese Counting rods |
| Alphabetic numerals | |
| Abjad Armenian Āryabhaṭa Cyrillic |
Ge'ez Greek Georgian Hebrew |
| Other systems | |
| Aegean Attic Babylonian Brahmi Egyptian Etruscan Inuit |
Kharosthi Mayan Quipu Roman Sumerian Urnfield |
| List of numeral system topics | |
| Positional systems by base | |
| Decimal (10) | |
| 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 16, 20, 24, 30, 36, 60, 64 | |
| Non-positional system | |
| Unary numeral system (Base 1) | |
| List of numeral systems | |
A septemvigesimal numeral system has a base of twenty-seven. It is used in two natural languages, the Telefol language and the Oksapmin language of Papua New Guinea.
Septemvigesimal notation can be used as a concise representation of ternary data, where each septemvigesimal digit represents three ternary digits. This is similar to using octal notation to represent binary data, though the digit set is closer in size to hexadecimal.
Examples: (Digits 10–26 are represented by letters A through Q.)
| Decimal | Ternary | Septemvigesimal |
|---|---|---|
| 0 | 000 | 0 |
| 1 | 001 | 1 |
| 2 | 002 | 2 |
| 3 | 010 | 3 |
| 5 | 012 | 5 |
| 10 | 101 | A |
| 15 | 120 | F |
| 20 | 202 | K |
| 25 | 221 | P |
| 26 | 222 | Q |
| 27 | 1000 | 10 |
| 81 | 10000 | 30 |
An alternate encoding, mapping 0 to space and 1–26 to A–Z, is occasionally used in puzzles to transform ternary triplets into words or messages.