490

Number

$490$ (four hundred and ninety) is:

$2 \times 5 \times 7^2$

The $11$th primitive semiperfect number after $6$, $20$, $28$, $88$, $104$, $272$, $304$, $350$, $368$, $464$:

$490 = 2 + 5 + 7 + 14 + 49 + 70 + 98 + 245$

The number of integer partitions for $19$:

$\map p {19} = 490$

The smallest positive integer which can be expressed as the sum of $2$ distinct lucky numbers in $23$ different ways

The $48$th noncototient after $10$, $26$, $34$, $50$, $\ldots$, $386$, $394$, $404$, $412$, $436$, $466$, $470$, $474$, $482$:

$\nexists m \in \Z_{>0}: m - \map \phi m = 490$

where $\map \phi m$ denotes the Euler $\phi$ function