2147
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Number
$2147$ (two thousand, one hundred and forty-seven) is:
- $19 \times 113$
- The $38$th pentagonal number after $1$, $5$, $12$, $22$, $35$, $\ldots$, $925$, $1001$, $1080$, $1162$, $1247$, $1335$, $1426$, $1520$, $1617$, $1717$, $1820$, $1926$, $2035$:
- $2147 = \ds \sum_{k \mathop = 1}^{38} \paren {3 k - 2} = \dfrac {38 \paren {3 \times 38 - 1} } 2$
- The $75$th generalized pentagonal number after $1$, $2$, $5$, $7$, $12$, $15$, $\ldots$, $1617$, $1650$, $1717$, $1751$, $1820$, $1855$, $1926$, $1962$, $2072$:
- $2147 = \ds \sum_{k \mathop = 1}^{38} \paren {3 k - 2} = \dfrac {38 \paren {3 \times 38 - 1} } 2$