21,480

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Number

$21 \, 480$ (twenty-one thousand, four hundred and eighty) is:

$2^3 \times 3 \times 5 \times 179$

The $22$nd integer $m$ such that $m! - 1$ (its factorial minus $1$) is prime:

$3$, $4$, $6$, $7$, $12$, $14$, $30$, $32$, $33$, $38$, $94$, $166$, $324$, $379$, $469$, $546$, $974$, $1963$, $3507$, $3610$, $6917$, $21 \, 480$

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