2,185,095

Number
$2 \, 185 \, 095$ (two million, one hundred and eighty-five thousand and ninety-five) is:


 * $3 \times 5 \times 11 \times 17 \times 19 \times 41$


 * The $2090$th triangular number:
 * $1 \, 747 \, 515 = \displaystyle \sum_{k \mathop = 1}^{2090} k = \dfrac {2090 \times \left({2090 + 1}\right)} 2$


 * The $2$nd of the $26$th pair of triangular numbers whose sum and difference are also both triangular:
 * $1 \, 747 \, 515 = T_{1869}$, $2 \, 185 \, 095 = T_{2090}$, $2 \, 185 \, 095 + 1 \, 747 \, 515 = T_{2804}$, $2 \, 185 \, 095 - 1 \, 747 \, 515 = T_{935}$