1361

This number is a prime.

1361, 136361, 13636361, 1363636361 and 136363636361 are primes, but 13636363636361 is composite.

The sum of squares of the first seven Lucas numbers. [Gallardo]

The sum of the first thirteen terms in the Lucas sequence. Note that 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 + 521 = 1361. [Schiffman]

The smallest mountain prime formed by concatenating two primes is simultaneously the 8th mountain prime in the sequence of mountain primes and the 8th Honaker prime in the sequence of Honaker primes. [Loungrides]

The smallest Honaker prime that is also a Honaker prime in binary representation. [Gaydos]

(There are 2 curios for this number that have not yet been approved by an editor.)