19991

This number is a prime.

+ The smallest primemirp that is also an invertible prime. [Bhattacharya]

+ The larger of the only two five-digit palindromic primes formed from two primes (19 and 991), one of which is the sum of the digits of the other. [Silva]

+ The smallest palindromic prime that is the sum of 17 consecutive prime numbers (1109 + ... + 1231 = 19991). [Schuler]

+ The smallest palindromic Sophie Germain prime p such that p! and p^p both contain p as a string of the digits. Note that 19991 is an invertible prime also. [Bajpai]

(There is one curio for this number that has not yet been approved by an editor.)

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