1321

This number is a prime.

+ π(1321) = 13 * 33 * 23 * 13. [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]

+ For any prime n < 10^11 there is a k such that either n*2^k + 1 or n*2^k - 1 has all its prime factors greater than 1321. [Wesolowski]

+ It requires 1321 gallons of water to make one ream of paper. [Seametrics]

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