18181
This number is a prime.
A palindromic prime equal to the sum of the reversals of three consecutive primes: 7237, 7243, 7247 -> 7327 + 3427 + 7427 = 18181. [Silva]
The smallest almost plateau prime. (An almost plateau prime
is a palindromic prime of the form abb...bab...bba, where a
is smaller than b.) [Loungrides]
The smallest palindromic prime formed by concatenating n, n and 1. [Devesh]
18181 is strobogrammatic and well as a tetradic prime. [Bajpai]
The smallest strobogrammatic palindromic prime of the form primemirp. [Pendergraft]
The only palindromic prime P that is the sum of the squares
of the first n oban numbers, i.e., (3^2 + 5^2 + 6^2 +...+
39^2 + 50^2), (case n=30). Curiously, sod(P) is the
smallest invertible prime. [Bajpai]