# 1321

This number is a prime.

1321 is an emirp and ((1321!)/(1231!))-1231 is prime. [Patterson]

π(1321) = 1^{3} * 3^{3} * 2^{3} *
1^{3}. [Caldwell]

The smallest emirp that splits up into two consecutive Fibonacci numbers: 13, 21. Note that the digits consist of the first four nonzero Fibonacci numbers. [Beedassy]

A prime formed from first Fiboncacci numbers that can be expressed by first semiprimes raised to first primes: 4^5+6^3+9^2. [Silva]

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

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