6

This number is a composite.

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

The smallest invertible brilliant number. [Capelle]

The lowest composite number containing distinct prime factors that cannot be expressed as the sum of two distinct prime numbers. [Capelle]

The smallest invertible semiprime. [Capelle]

The smallest number whose factorial is a product of two factorials of primes (6! = 3!5!). Note that 6 is one of these factorials, in accordance with the equation (n!)! = n!(n! - 1)! [Capelle]

The number of prime Euler's "numeri idonei". [Capelle]