1330

Number
$1330$ (one thousand, three hundred and thirty) is:
 * $2 \times 5 \times 7 \times 19$


 * The $19$th tetrahedral number, after $1$, $4$, $10$, $20$, $35$, $56$, $84$, $120$, $165$, $220$, $286$, $364$, $455$, $560$, $680$, $816$, $969$, $1140$:
 * $1330 = \ds \sum_{k \mathop = 1}^{19} \frac {k \paren {k + 1} } 2 = \dfrac {19 \paren {19 + 1} \paren {19 + 2} } 6$


 * The $23$rd primitive semiperfect number after $6$, $20$, $28$, $88$, $104$, $\ldots$, $572$, $650$, $748$, $770$, $910$, $945$, $1184$, $1190$, $1312$:
 * $1330 = 2 + 5 + 7 + 14 + 35 + 38 + 70 + 95 + 133 + 266 + 665$

Also see

 * Tau Function of 1330