1653

Number
$1653$ (one thousand, six hundred and fifty-three) is:
 * $3 \times 19 \times 29$


 * The $29$th hexagonal number after $1, 6, 15, 28, 45, 66, 91, \ldots, 703, 780, 861, 946, 1035, 1225, 1326, 1431, 1540$:
 * $1653 = \displaystyle \sum_{k \mathop = 1}^{29} \left({4 k - 3}\right) = 29 \left({2 \times 29 - 1}\right)$