noun ·Rare ·Advanced level

Definitions

Noun

1. 1
   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, ..."

Example

More examples

"The sequence of emirps begins: 13, 17, 31, 37, 71, 73, 79, 97, 107, ..."

Etymology

prime spelled backwards.

Related phrases

prime number

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.