MathNet 2021 — Part 09 Question 99

For $n$ a positive integer, let $f(n)$ be the quotient obtained when the sum of all positive divisors of $n$ is divided by $n$. For example, $f(14) = (1 + 2 + 7 + 14) \div 14 = \frac{12}{7}$. What is $f(768) - f(384)$ ?