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]

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