736

Number
$736$ (seven hundred and thirty-six) is:


 * $2^5 \times 23$


 * The $16$th octagonal number, after $1$, $8$, $21$, $40$, $65$, $96$, $133$, $176$, $225$, $280$, $341$, $408$, $481$, $560$, $645$:
 * $736 = \displaystyle \sum_{k \mathop = 1}^{16} \left({6 k - 5}\right) = 16 \left({3 \times 16 - 2}\right)$