Call a positive integer n k-pretty if n has exactly k positive divisors and n is divisible by k. For example, 18 is 6 -pretty. Let S be the sum of positive integers less than 2019 that are 20-pretty. Find \frac{S}{20}.
Call a positive integer n k-pretty if n has exactly k positive divisors and n is divisible by k. For example, 18 is 6 -pretty. Let S be the sum of positive integers less than 2019 that are 20-pretty. Find \frac{S}{20}.