1431

Number
$1431$ (one thousand, four hundred and thirty-one) is:
 * $3^3 \times 53$


 * The $27$th hexagonal number after $1, 6, 15, 28, 45, 66, 91, \ldots, 703, 780, 861, 946, 1035, 1225, 1326$:
 * $1431 = \displaystyle \sum_{k \mathop = 1}^{27} \left({4 k - 3}\right) = 27 \left({2 \times 27 - 1}\right)$