| ||||
|---|---|---|---|---|
| Cardinal | forty | |||
| Ordinal | 40th (fortieth) | |||
| Numeral system | quadragesimal | |||
| Factorization | 23 × 5 | |||
| Divisors | 1, 2, 4, 5, 8, 10, 20, 40 | |||
| Greek numeral | Μ´ | |||
| Roman numeral | XL | |||
| Latin prefix | quadrage- | |||
| Binary | 1010002 | |||
| Ternary | 11113 | |||
| Senary | 1046 | |||
| Octal | 508 | |||
| Duodecimal | 3412 | |||
| Hexadecimal | 2816 | |||
| Armenian | Խ | |||
| Hebrew | מ / ם | |||
| Babylonian numeral | 𒐏 | |||
| Egyptian hieroglyph | 𓎉 | |||
40 (forty) is the natural number following 39 and preceding 41.
Though the word is related to four (4), the spelling forty replaced fourty during the 17th century[1][2] and is now the standard form.