2380

Number
$2380$ (two thousand, three hundred and eighty) is:


 * $2^2 \times 5 \times 7 \times 17$


 * The $40$th pentagonal number after $1$, $5$, $12$, $22$, $35$, $\ldots$, $1820$, $1926$, $2035$, $2147$, $2262$:
 * $2380 = \displaystyle \sum_{k \mathop = 1}^{40} \left({3 k - 2}\right) = \dfrac {40 \left({3 \times 40 - 1}\right)} 2$