2147

Number
$2147$ (two thousand, one hundred and forty-seven) is:


 * $19 \times 113$


 * The $38$th pentagonal number after $1$, $5$, $12$, $22$, $35$, $\ldots$, $925$, $1001$, $1080$, $1162$, $1247$, $1335$, $1426$, $1520$, $1617$, $1717$, $1820$, $1926$, $2035$:
 * $2147 = \displaystyle \sum_{k \mathop = 1}^{38} \left({3 k - 2}\right) = \dfrac {38 \left({3 \times 38 - 1}\right)} 2$