1657

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


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