2628

Number
$2628$ (two thousand, six hundred and twenty-eight) is:
 * $2^2 \times 3^2 \times 73$


 * The $72$nd triangular number after $1$, $3$, $6$, $10$, $15$, $\ldots$, $2211$, $2278$, $2346$, $2415$, $2485$, $2556$:
 * $2628 = \displaystyle \sum_{k \mathop = 1}^{72} k = \dfrac {72 \times \left({72 + 1}\right)} 2$