40 (number)

natural number

40 (forty) is the number that is after thirty-nine and before forty-one.

← 39 40 41 →
Cardinalforty
Ordinal40th
(fortieth)
Factorization23× 5
Greek numeralΜ´
Roman numeralXL
Binary1010002
Ternary11113
Quaternary2204
Quinary1305
Senary1046
Octal508
Duodecimal3412
Hexadecimal2816
Vigesimal2020
Base 361436

The prime factors of forty are 2 and 5. (2 * 2 * 2 * 5 = 40)

Forty is also the only number in the English language which is spelt in alphabetical order.

The Bible

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In the Judeo-Christian Bible, the number forty has special meaning. The Jews wandered in a desert for forty years, there was a forty-day and forty-night rainstorm, and other instances.

Factors of 40

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The factors of 40 are 1, 2, 4, 5, 8, 10, 20 and 40.