This number is a composite.

+ Using 10213 as the starting term for the RATS algorithm: Reverse Add Then Sort the digits, leads to a 72 term sequence ending with the prime 5566666666666666666667777. This is the longest sequence produced for all starting integers < 20000 using the prime stopping criterion. [Earls]

Printed from the PrimePages <primes.utm.edu> © G. L. Honaker and Chris K. Caldwell