"HAHAHAHAHAHAHAHAHAHHHHAAA BAZINGA" --Sheldon fan
42 is an even integer with prime factorization of 2 * 3 * 7. This number was made kind of famous (and later overused in pop culture to the point of completely destroying the joke) by Douglas Adams' book The Hitchhiker's Guide to the Galaxy in which it appears as the answer to the ultimate question of life, the Universe and everything (the point of the joke was that this number was the ultimate answer computed by a giant supercomputer over millions of years, but it was ultimately useless as no one knew the question to which this number was the answer).
If you make a 42 reference in front of a TBBT fan, he will shit himself.
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