16661

This number is a prime.

The smallest palindromic beastly prime.

16661 is the 1928th prime. Note that 1 + 6 + 6 + 6 + 1 = 1 + 9 + 2 + 8. (See "The Most Evil Number" on Numberphile @ time 2:00.)

The smallest invertible palindromic prime. [Capelle]

16661 divides 9⁴⁹ + 1. [De Geest]

The smallest palindromic beastly prime that is the sum of 9 consecutive primes. [Green]

16661 is congruent to 11 (mod 666), an expression containing the exact digits of the palindromic prime itself. [Green]

The only known invertible beastly Honaker prime. [Loungrides]

The smallest palindromic Honaker prime p such that p! and p^p both contain p as a string of digits. [Bajpai]

16661*(16661+1)+1 is prime. [Sariyar]

The smallest of the five "full house" Honaker primes. [Gaydos]