1431

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


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