970

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


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