58

Number
$58$ (fifty-eight) is:
 * $2 \times 29$


 * The $6$th noncototient after $10, 26, 34, 50, 52$:
 * $\nexists m \in \Z_{>0}: m - \phi \left({m}\right) = 58$
 * where $\phi \left({m}\right)$ denotes the Euler $\phi$ function