4347

Number
$4347$ (four thousand, three hundred and forty-seven) is:
 * $3^3 \times 7 \times 23$


 * The $42$nd heptagonal number after $1, 7, 18, 34, 55, 81, 112, \ldots, 3010, 3186, 3367, 3553, 3744, 3940, 4141$:
 * $4347 = \displaystyle \sum_{k \mathop = 1}^{42} \left({5 k - 4}\right) = \dfrac {42 \left({5 \times 42 - 3}\right)} 2$