5221

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


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