404

Number
$404$ (four hundred and four) is:


 * $2^2 \times 101$


 * The $41$st noncototient after $10, 26, 34, 50, \ldots, 344, 346, 362, 366, 372, 386, 394$:
 * $\nexists m \in \Z_{>0}: m - \phi \left({m}\right) = 404$
 * where $\phi \left({m}\right)$ denotes the Euler $\phi$ function


 * The $8$th even integer after $2, 4, 94, 96, 98, 400, 402$ that cannot be expressed as the sum of $2$ prime numbers which are each one of a pair of twin primes.