An array $A$ of length $n = 3901585$, is defined by $A[i] = i^i$ $(1 \le i \le n)$.

A forward difference array is the array formed by the differences of consecutive elements, i.e. $[{a_1, a_2, a_3}]$ is replaced by $[{a_2-a_1, a_3-a_2}]$.

Calculate the only value remaining in the $(n - 1)^{th}$ forward difference array of $A$ modulo $1,000,000,007$.