9126

Number
$9126$ (nine thousand, one hundred and twenty-six) is:


 * $2 \times 3^3 \times 13^2$


 * The $26$th pentagonal pyramidal number after $1$, $6$, $12$, $40$, $75$, $\ldots$, $1470$, $1800$, $2176$, $2601$, $3078$, $3610$, $4200$, $4851$, $5566$, $6348$, $7200$, $8125$:
 * $9126 = \ds \sum_{k \mathop = 1}^{26} \dfrac {k \paren {3 k - 1} } 2 = \dfrac {26^2 \paren {26 + 1} } 2$