Find the sum of the positive square free divisors of 5400.

Consider the positive squares of 1,2,3,4, 5, ...

They are 1, 4, 9, 16, 25, ...

Factorize 5400 with regard to these positive squares.

5400 = 4 * 1350

= 4 * 9 * 150

= 4 * 9 * 25 * 6

The positive square free divisors of 5400 are 4,9 and 25.

Their sum is 4+9+25 = 38

Answer: 38