970

Number
$970$ (nine hundred and seventy) is:
 * $2 \times 5 \times 97$


 * The $20$th heptagonal number after $1$, $7$, $18$, $34$, $55$, $81$, $112$, $148$, $189$, $235$, $286$, $342$, $403$, $469$, $540$, $616$, $697$, $783$, $874$:
 * $970 = \displaystyle \sum_{k \mathop = 1}^{20} \left({5 k - 4}\right) = \dfrac {20 \left({5 \times 20 - 3}\right)} 2$