1657

Number
$1657$ (one thousand, six hundred and fifty-seven) is:
 * The $260$th prime number


 * The $24$th centered hexagonal number after $1$, $7$, $19$, $37$, $61$, $91$, $127$, $\ldots$, $817$, $919$, $1027$, $1141$, $1261$, $1387$, $1519$:
 * $1657 = \displaystyle 1 + \sum_{k \mathop = 1}^{24 - 1} 6 k = 24^3 - 23^3$