7701

Number
$7701$ (seven thousand, seven hundred and one) is:
 * $3 \times 17 \times 151$


 * The $51$st octagonal number, after $1$, $8$, $21$, $40$, $65$, $\ldots$, $5985$, $6256$, $6533$, $6816$, $7105$, $7400$:
 * $7701 = \ds \sum_{k \mathop = 1}^{51} \paren {6 k - 5} = 51 \paren {3 \times 51 - 2}$