242 (number)

← 241 242 243 →
Cardinaltwo hundred forty-two
Ordinal242nd
(two hundred forty-second)
Factorization2 × 112
Greek numeralΣΜΒ´
Roman numeralCCXLII
Binary111100102
Ternary222223
Senary10426
Octal3628
Duodecimal18212
HexadecimalF216

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.[3]

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

(This fraction is slightly larger than , by a factor of around )

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

References

[edit]
  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.
  3. ^ Sloane, N. J. A. (ed.). "Sequence A006958 (Number of parallelogram polyominoes with n cells (also called staircase polyominoes, although that term is overused))". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.