2839

Number
$2839$ (two thousand, eight hundred and thirty-nine) is:
 * $17 \times 167$


 * The $34$th heptagonal number after $1, 7, 18, 34, 55, 81, 112, \ldots, 2205, 2356, 2512, 2673$:
 * $2839 = \displaystyle \sum_{k \mathop = 1}^{34} \left({5 k - 4}\right) = \dfrac {34 \left({5 \times 34 - 3}\right)} 2$