180

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


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


 * The $4$th number after $1$, $9$, $20$ whose square has a divisor sum which is itself square:


 * The $11$th highly composite number after $1$, $2$, $4$, $6$, $12$, $24$, $36$, $48$, $60$, $120$:
 * $\map \tau {180} = 18$


 * The $11$th superabundant number after $1$, $2$, $4$, $6$, $12$, $24$, $36$, $48$, $60$, $120$:
 * $\dfrac {\map {\sigma_1} {180} } {180} = \dfrac {546} {180} = 3 \cdotp 0 \dot 3$


 * The $26$th highly abundant number after $1$, $2$, $3$, $4$, $6$, $8$, $10$, $12$, $16$, $18$, $20$, $24$, $30$, $36$, $42$, $48$, $60$, $72$, $84$, $90$, $96$, $108$, $120$, $144$, $168$:
 * $\map {\sigma_1} {180} = 546$


 * $180^3 = 6^3 + 7^3 + \cdots + 67^3 + 68^3 + 69^3$


 * The number of degrees in the sum of the internal angles of a triangle

Also see

 * Measurement of Straight Angle
 * Sum of Angles of Triangle equals Two Right Angles
 * Cube of 180 is Sum of Sequence of Consecutive Cubes