5688

Number
$5688$ (five thousand, six hundred and eighty-eight) is:
 * $2^2 \times 29 \times 47$


 * The $48$th heptagonal number after $1$, $7$, $18$, $34$, $55$, $81$, $112$, $\ldots$, $3744$, $3940$, $4141$, $4347$, $4558$, $4774$, $4995$, $5221$, $5452$:
 * $5688 = \ds \sum_{k \mathop = 1}^{48} \paren {5 k - 4} = \dfrac {48 \paren {5 \times 48 - 3} } 2$