2420

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Number

$2420$ (two thousand, four hundred and twenty) is:

$2^2 \times 5 \times 11^2$


The $40$th second pentagonal number after $2$, $7$, $15$, $26$, $\ldots$, $1751$, $1855$, $1962$, $2072$, $2185$, $2301$:
$2420 = \dfrac {40 \paren {3 \times 40 + 1} } 2$


The $80$th generalized pentagonal number after $1$, $2$, $5$, $7$, $12$, $15$, $\ldots$, $2072$, $2147$, $2185$, $2262$, $2301$, $2380$:
$2420 = \dfrac {40 \paren {3 \times 40 + 1} } 2$


Also see