5221

Number
$5221$ (five thousand, two hundred and twenty-one) is:
 * $23 \times 227$


 * The $46$th heptagonal number after $1$, $7$, $18$, $34$, $55$, $81$, $112$, $\ldots$, $3744$, $3940$, $4141$, $4347$, $4558$, $4774$, $4995$:
 * $5221 = \ds \sum_{k \mathop = 1}^{46} \paren {5 k - 4} = \dfrac {46 \paren {5 \times 46 - 3} } 2$