242 (number) explained

242 (two hundred [and] forty-two) is the natural number following 241 and preceding 243.

242 is the smallest integer to start a run of four consecutive integers with the same number of divisors.^{[1] [2]}

242 is a nontotient since there is no integer with 242 coprimes below it.

242 is a palindrome.

242 is the number of parallelogram polyominoes with 8 cells.

242 is the difference between 355 and 113, two numbers used in an approximation of pi,

(355)/(113) = 3 . 14159292035 \ldots

(This fraction is slightly larger than

\pi , by a factor of around 0 . 000000266764... )

242 is the sum of elements in a 5-orthoplex: 32 polychora, 80 cells, 80 faces, 40 edges, and 10 vertices.

Notes and References

1. R. K. Guy Unsolved Problems in Number Theory, section B18.
2. D. Wells, The Penguin Dictionary of Curious and Interesting Numbers, Penguin Books, NY, 1986: 147, 176.