42 (number)

This article is about the number 42. For the year, see 42.

42 (forty-two) is a number. It comes between forty-one and forty-three, and is an even number. It is divisible by 1, 2, 3, 6, 7, 14, 21, and 42.

← 41 42 43 →
← 40 41 42 43 44 45 46 47 48 49 → List of numbers — Integers ← 0 10 20 30 40 50 60 70 80 90 →
Cardinal	forty-two
Ordinal	42nd (forty-second)
Factorization	2 × 3 × 7
Greek numeral	ΜΒ´
Roman numeral	XLII
Binary	1010102
Ternary	11203
Quaternary	2224
Quinary	1325
Senary	1106
Octal	528
Duodecimal	3612
Hexadecimal	2A16
Vigesimal	2220
Base 36	1636

42 is an extremely interesting number to mathematicians, because of its many features. For example:

1. It is the product of two consecutive integers (6 and 7), making it a pronic number.
2. It is the second sphenic number, the product of three distinct prime numbers.
3. It is an abundant number, the sum of its proper divisors is greater than the number itself.

There are at least a dozen more features of interest to number theory enthusiasts.

Appearance in literature

"42" is the "Answer to the Ultimate Question of Life, the Universe, and Everything" in Douglas Adams' The Hitchhiker's Guide to the Galaxy books.

The number makes regular appearances in Lewis Carroll's writings, such as in The Hunting of the Snark. Rule Forty-two in Alice's Adventures in Wonderland is "All persons more than a mile high to leave the court". Charles Dodgson was a mathematician.