180

Number
$180$ (one hundred and eighty) is:


 * $2^2 \times 3^2 \times 5$


 * The $11$th superabundant number after $1, 2, 4, 6, 12, 24, 36, 48, 60, 120$:
 * $\dfrac {\sigma \left({180}\right)} {180} = \dfrac {546} {180} = 3 \cdotp 0 \dot 3$


 * The $4$th number after $1, 9, 20$ whose square has a $\sigma$ value which is itself square: