124

Number
$124$ (one hundred and twenty-four) is:


 * $2^2 \times 31$


 * The $17$th nontotient after $14, 26, 34, 38, 50, 62, 68, 74, 76, 86, 90, 94, 98, 114, 118, 122$:
 * $\nexists m \in \Z_{>0}: \phi \left({m}\right) = 124$
 * where $\phi \left({m}\right)$ denotes the Euler $\phi$ function


 * The $7$th untouchable number after $2, 5, 52, 88, 96, 120$.


 * The $3$rd even integer that cannot be expressed as the sum of $2$ prime numbers of which the smaller one is $3$, $5$ or $7$.


 * The $55$th positive integer after $2$, $3$, $4$, $7$, $8$, $\ldots$, $95$, $96$, $100$, $101$, $102$, $107$, $112$, $116$ which cannot be expressed as the sum of distinct pentagonal numbers.