1770

Number
$1770$ (one thousand, seven hundred and seventy) is:
 * $2 \times 3 \times 5 \times 59$


 * The $30$th hexagonal number after $1, 6, 15, 28, 45, 66, 91, \ldots, 703, 780, 861, 946, 1035, 1225, 1326, 1431, 1540, 1653$:
 * $1770 = \displaystyle \sum_{k \mathop = 1}^{30} \left({4 k - 3}\right) = 30 \left({2 \times 30 - 1}\right)$