2625

Number
$2625$ (two thousand, six hundred and twenty-five) is:


 * $3 \times 5^3 \times 7$


 * The $42$nd pentagonal number after $1$, $5$, $12$, $22$, $35$, $\ldots$, $1820$, $1926$, $2035$, $2147$, $2262$, $2380$, $2501$:
 * $2625 = \displaystyle \sum_{k \mathop = 1}^{42} \left({3 k - 2}\right) = \dfrac {42 \left({3 \times 42 - 1}\right)} 2$