Euler's Totient function, `phi(n)` [sometimes called the phi function], 
is used to determine the number of positive numbers less than or equal to n which are relatively prime to n. 
For example, as 1, 2, 4, 5, 7, and 8, are all less than nine and relatively prime to nine, `phi(9)=6`.

The number 1 is considered to be relatively prime to every positive number, so `phi(1)=1`.

Interestingly, `phi(87109)=79180`, and it can be seen that `87109` is a permutation of `79180`.

Find the value of `n`, `1 < n < 10^7`, for which `phi(n)` is a permutation of n and the ratio `n/phi(n)` produces a minimum.