# 31723

This number is a prime.

Pope Pius IX officially ended his reign as pontiff after 31 years, 7 months and 23 days. Note that 31, 7, 23, and 31723 are all prime numbers. [Rivera]

The concatenation of the indices of two consecutive repunit primes (R_{317} and R_{23}) is an emirp. [Loungrides]

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