Forty-two is a pronic number, meaning that it is a number that is a product of two consecutive integers. In this case, 6 and 7.
Forty-two is an abundant number, meaning that the sum of its divisors -- 1, 2, 3, 6, 7, 14, 21, and 42, totalling 96 -- is more than the sum of twice the number.
Forty-two is also a sphenic number, a positive integer which is the product of three primes, in this case, 2, 3, and 7.
On top of all that, forty-two is also a primary pseudoperfect number, a Catalan number, a pentedecagonal number, a Stormer number and a meandric number.
An interesting thought experiment:
In 1966, mathematician Paul Cooper theorized that the fastest, most efficient way to travel across continents would be to bore a straight hollow tube directly through the Earth, connecting a set of antipodes, evacuate it (remove the air), and then just fall through. The time for such a journey works out to be 42 minutes.
Lewis Carroll worked out something similar, but without computations. Forty-two features prominently in many of Carroll's works.
In Japanese culture, though, 42 is considered unlucky.
And, of course, it is The Answer to the Ultimate Question of Life, the Universe, and Everything. Writer Douglas Adams, however, calls it a joke.
The answer to this is very simple. It was a joke. It had to be a number, an ordinary, smallish number, and I chose that one. Binary representations, base thirteen, Tibetan monks are all complete nonsense. I sat at my desk, stared into the garden and thought '42 will do' I typed it out. End of story.
And finally: I am 42 years old today.