833

Number
$833$ (eight hundred and thirty-three) is:


 * $7^2 \times 17$


 * The $17$th octagonal number, after $1$, $8$, $21$, $40$, $65$, $96$, $133$, $176$, $225$, $280$, $341$, $408$, $481$, $560$, $645$, $736$:
 * $833 = \displaystyle \sum_{k \mathop = 1}^{17} \left({6 k - 5}\right) = 17 \left({3 \times 17 - 2}\right)$