emirp

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English[edit]

Etymology[edit]

prime spelled backwards.

Noun[edit]

emirp (plural emirps)

  1. (number theory) A prime number that becomes a different prime when its decimal digits (or digits in some specified other base) are reversed.
    The sequence of emirps begins: 13, 17, 31, 37, 71, 73, 79, 97, 107, ...
    The first few emirps in base 12 (using the convention T for ten and E for eleven) are: 15, 51, 57, 5E, 75, E5, 107, ...
    • 1986, Malcolm E. Lines, A Number for your Thoughts, Taylor & Francis, page 39:
      Therefore we do not yet know whether the general emirps go on forever or whether they too eventually end with a largest emirp of all.

Usage notes[edit]

  • A palindromic prime is not considered an emirp.
  • The term reversible prime is generally synonymous with emirp, but sometimes includes palindromic primes. (See Emirp on Wikipedia.Wikipedia )

Further reading[edit]

Anagrams[edit]

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