969

Number
$969$ (nine hundred and sixty-nine) is:
 * $3 \times 17 \times 19$


 * The $17$th tetrahedral number, after $1$, $4$, $10$, $20$, $35$, $56$, $84$, $120$, $165$, $220$, $286$, $364$, $455$, $560$, $680$, $816$:
 * $969 = \displaystyle \sum_{k \mathop = 1}^{17} \frac {k \left({k + 1}\right)} 2 = \dfrac {17 \left({17 + 1}\right) \left({17 + 2}\right)} 6$