This number is a prime.

+ The largest prime formed from a double-digit prime p, (p=61), by writing right-to-left the sums of digits which precede it, so that all the previous numbers, that are produced by this process, are primes, i.e., 761, 41761, 9141761, 929141761. [Loungrides]

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