# Arithmetic Derivative

An arithmetic derivative calculator that uses these simple formulas:
* 0' = 1' = 0;
* if n is a prime, n' = 1;
* if n = ab  (a and b > 1), n' = a'b + ab'
* (-n)' = -(n')

More about arithmetic derivative:
https://en.wikipedia.org/wiki/Arithmetic_derivative