970

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


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