8965

Number
$8965$ (eight thousand, nine hundred and sixty-five) is:


 * $5 \times 11 \times 163$


 * The $55$th octagonal number, after $1$, $8$, $21$, $40$, $65$, $\ldots$, $5985$, $6256$, $6533$, $6816$, $7105$, $7400$, $7701$, $8008$, $8321$, $8640$:
 * $8965 = \displaystyle \sum_{k \mathop = 1}^{55} \left({6 k - 5}\right) = 55 \left({3 \times 55 - 2}\right)$