I am a prime number. If you reverse my digits, I become a different prime number, and the absolute difference between us is 18. What number am I?
13
13 is prime, and its reverse is 31 (also prime). The absolute difference between 31 and 13 is 18.
About this riddle
Math riddles hide a calculation inside a short story. Pull out the numbers, work out what is being asked, and watch for a trick such as a unit change.
Difficulty: Hard. More like this: Math riddles with answers or try Target 24 for a different kind of puzzle.
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