40 (number)

CardinalfortyOrdinal40th
(fortieth)Numeral systemquadragesimalFactorization2 × 5Divisors1, 2, 4, 5, 8, 10, 20, 40Greek numeralΜ´Roman numeralXL, xlLatinprefixquadrage-Binary101000₂Ternary1111₃Senary104₆Octal50₈Duodecimal34₁₂Hexadecimal28₁₆ArmenianԽHebrewמ / םBabylonian numeral𒐏Egyptian hieroglyph𓎉

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 and is now the standard form.