For a positive integer $n$, $\phi(n)$ denotes the number of positive integers less than or equal to $n$ that are relatively prime to $n$. What is $\phi(1200)$?
1200 = 12 * 5^2 * 2^2 = 2^4 * 3 * 5^2
Using Euler's Totient Function
phi (1200) = 1200 / ( 2 * 3 * 5) * (2-1)(3-1) (5-1) = 40 (1)(2)(4) = 320
phi(1200) = 1050
+1375 
