This number is a composite.

+ The first base in which KJIHGFEDCBA987654321 is a prime. All shorter such strings achieve prime status in much smaller bases (192 is the maximum required), and not until the string (110)(109)(108)...321 is a higher base required. [Merickel]

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