# 128

This number is a composite.

128 = 2! + 3! + 5!. [Petersen]

128 + (1 + 2 + 8) is prime. Note that 1 * 2 * 8 divides 128. [Capelle]

The largest known even number that can be expressed as the sum of two primes in exactly three ways. [Capelle]

Smallest positive integer k>=2 such that no primes of the form (k-1)*k^n-1, with positive integer n, are known. [Luen]

Are 127 and 131 the largest cousin primes with a power of two (128) between them? [Gaydos]

(There is one curio for this number that has not yet been approved by an editor.)

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