2145

Number
$2145$ (two thousand, one hundred and forty-five) is:
 * $3 \times 5 \times 11 \times 13$


 * The $33$rd hexagonal number after $1$, $6$, $15$, $28$, $45$, $66$, $91$, $\ldots$, $703$, $780$, $861$, $946$, $1035$, $1225$, $1326$, $1431$, $1540$, $1653$, $1770$, $1891$, $2016$:
 * $2145 = \displaystyle \sum_{k \mathop = 1}^{33} \left({4 k - 3}\right) = 33 \left({2 \times 33 - 1}\right)$