3486

Number
$3486$ (three thousand, four hundred and eighty-six) is:


 * $2 \times 3 \times 7 \times 83$


 * The $42$nd hexagonal number after $1$, $6$, $15$, $28$, $45$, $66$, $91$, $\ldots$, $2145$, $2278$, $2415$, $2556$, $2701$, $2850$, $3003$, $3160$, $3321$:
 * $3486 = \displaystyle \sum_{k \mathop = 1}^{42} \left({4 k - 3}\right) = 42 \left({2 \times 42 - 1}\right)$