I'm trying to solve other problems of the same type. I have that phi(x) = 13,000,000.
Since the prime factorization of 13,000,000 is 265613, I wrote that phi(2l)phi(5m)phi(13n) = 2l-1(1)5m-1(4)13n-1(12).
I can express 4 as 22, but 12 = 3*22, and I don't see how to get 3 out of the...