I am trying to figure out how to compute \varphi(22) and \varphi(24)
22 = 2*11
phi(22) = (1 - 1/2)*(1 - 1/11)*22 = (1/2)*(10/11)*22 = 1*10 = 10.
24 = (2^3)*3
phi(24) = (1 - 1/2)*(1 - 1/3)*24 = (1/2)*(2/3)*24 = 2*4 = 8.
http://en.wikipedia.org/wiki/Euler's_totient_function