For every integer n>1, the family of functions f_n,a,b is defined by f_n,a,b(x)≡ax+b mod n for a,b,x integer and 0<a<n, 0≤b<n, 0≤x<n.
We will call f_n,a,b a retraction if f_n,a,b(f_n,a,b(x))≡f_n,a,b(x) mod n for every 0≤x<n.
Let R(n) be the number of retractions for n.

F(N)=∑R(n⁴+4) for 1≤n≤N.
F(1024)=77532377300600.

Find F(10⁷) (mod 1 000 000 007)