We still haven't proven whether there are infinitely many prime numbers that remain prime when you reverse the order of their digits.
open
Mathematics & Logic
Palindromic and reversible primes show interesting patterns, but whether infinitely many exist across all number bases remains unconfirmed. This is one of many number-theoretic curiosities still lacking rigorous proof.
Team Humans Club. (2026). Problem WS01269: We still haven't proven whether there are infinitely many prime numbers that remain prime when you reverse the order of their digits.. World Solve. Retrieved 20 Jul 2026, from https://worldsolve.org/index.php?id=1269