140

Number

$140$ (one hundred and forty) is:

$2^2 \times 5 \times 7$

With $195$, an element of the $2$nd quasiamicable pair:

$\map \sigma {140} = \map \sigma {195} = 336 = 140 + 195 + 1$

The $4$th Ore number after $1, 6, 28$:

$\dfrac {140 \times \map \tau {140} } {\map \sigma {140} } = 5$

and the $3$rd after $1, 6$ whose divisors also have an arithmetic mean which is an integer:

$\dfrac {\map \sigma {140} } {\map \tau {140} } = 28$

The $7$th square pyramidal number after $1$, $5$, $14$, $30$, $55$, $91$:

$140 = 1 + 4 + 9 + 16 + 25 + 36 + 49$

The $10$th integer $n$ after $1, 3, 15, 30, 35, 56, 70, 78, 105$ with the property that $\map \tau n \divides \map \phi n \divides \map \sigma n$:

$\map \tau {140} = 12$, $\map \phi {140} = 48$, $\map \sigma {140} = 336$