93

Number
$93$ (ninety-three) is:


 * $3 \times 31$


 * The $21$st lucky number:
 * $1$, $3$, $7$, $9$, $13$, $15$, $21$, $25$, $31$, $33$, $37$, $43$, $49$, $51$, $63$, $67$, $73$, $75$, $79$, $87$, $93$, $\ldots$


 * The $31$st semiprime:
 * $93 = 3 \times 31$