2617

This number is a prime.

The largest prime index of a mountain prime p in the sequence of mountain primes, i.e., p=123457897654321. [Loungrides]

The smallest anagraprod "anagram by product" prime. E.g., 2*6=12, 6*1=6, 1*7=7, and 2617 is composed of digits 1, 2, 6, and 7. [Angelini]