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42 (number)

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42 (forty-two) is the natural number following 41 and preceding 43.

Cardinal 42
forty-two
Ordinal 42nd
forty-second
Factorization2 × 3 × 7
Divisors 2, 3, 6, 7, 14, 21
Roman numeralXLII
Binary101010
Hexadecimal2A
IEEE Float42.0 = 42280000 hexadecimal
Hebrewמב (Mem Bet)

In mathematics

Bracketed by twin primes, this composite number's factorization makes it a sphenic number, as it is the product of the first three terms of Sylvester's sequence. It is also the third 15-gonal number, a Catalan number, a meandric number, an open meandric number. It is the sum of the totient function for the first eleven integers.

It is believed to be the third moment of the Riemann zeta function, based partially upon evidence from quantum mechanics.

In base 10, it is a Harshad number and a self number.

It is also a perfect score on the USA Math Olympiad (USAMO) and International Mathematical Olympiad (IMO).

42 is a repdigit in base 4 (222).

In science

Astronomy

In religion

In pop culture

The Ultimate Answer
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The Ultimate Answer

It is also interesting to note that 47 shares 42's status as a cult figure integer, and tongue-in-cheek legends concerning these numbers are numerous.

In sports

Jackie Robinson in his now-retired number 42 jersey.
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Jackie Robinson in his now-retired number 42 jersey.

In technology

42 is a common metasyntactic variable used by programmers. In the TIFF image file format, the second 16-bit word of every file is 42, which is used together with the first word to indicate byte order. In the reiser4 file system, 42 is the inode number of the root directory.

The code number for the Microsoft .NET platform is 42, since it is their answer to "The Answer to Life, the Universe, and Everything". It also happens to be the building number that the Microsoft .NET CLR is built in.

The help entry 42 (accessed by typing ":h 42" in command mode) in the Vim text editor displays a reference to Douglas Adams.

In other fields

External links

 


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All text is available under the terms of the GNU Free Documentation License See Wikipedia Copyrights for details.

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