588

This number is a composite.

Smallest even number k such that there are no known prime of the form 3*k^n-1. [Sevin]

The smallest number outside primes and prime powers, such that the sum of cubes of its prime factors (including multiplicity) is a perfect cube: 588 = 2 x 2 x 3 x 7 x 7 and 2³ + 2³ + 3³ + 7³ + 7³ = 9³. [Gudipati]