# 15

This number is a composite.

Just showing those entries submitted by 'Capelle': (Click here to show all)

15 is the smallest number which is product of two distinct odd primes. [Capelle]

The only known natural number n > 0 such that the sum of the five known Fermat primes raised to the power n is prime. Curiously, it is the product of the first two Fermat primes. [Capelle]

The number of supersingular primes, i.e., primes that
divide the order of the Monster group (an algebraic
construction with 2^{46} *
3^{20} *
5^{9} *
7^{6} *
11^{2} *
13^{3} * 17 * 19 * 23 * 29 * 31 *
41 * 47 * 59 * 71 elements). [Capelle]

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