7200
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Number
$7200$ (seven thousand, two hundred) is:
- $2^5 \times 3^2 \times 5^2$
- The $24$th pentagonal pyramidal number after $1$, $6$, $12$, $40$, $75$, $\ldots$, $1470$, $1800$, $2176$, $2601$, $3078$, $3610$, $4200$, $4851$, $5566$, $6348$:
- $7200 = \ds \sum_{k \mathop = 1}^{24} \dfrac {k \paren {3 k - 1} } 2 = \dfrac {24^2 \paren {24 + 1} } 2$