1045

Number
$1045$ (one thousand, one hundred and forty-five) is:


 * $5 \times 11 \times 19$


 * The $19$th octagonal number, after $1$, $8$, $21$, $40$, $65$, $96$, $133$, $176$, $225$, $280$, $341$, $408$, $481$, $560$, $645$, $736$, $833$, $936$:
 * $1045 = \displaystyle \sum_{k \mathop = 1}^{19} \left({6 k - 5}\right) = 19 \left({3 \times 19 - 2}\right)$