Products of Bi-Unitary Divisors (noch nicht übersetzt)
A unitary divisor of a positive integer $n$ is a divisor $d$ of $n$ such that $\gcd\left(d,\frac{n}{d}\right)=1$.
A bi-unitary divisor of $n$ is a divisor $d$ for which 1 is the only unitary divisor of $d$ that is also a unitary divisor of $\frac{n}{d}$.
For example, 2 is a bi-unitary divisor of 8, because the unitary divisors of 2 are {1,2}, and the unitary divisors of 8/2 are {1,4}, with 1 being the only unitary divisor in common.
The bi-unitary divisors of $240$ are $\{1,2,3,5,6,8,10,15,16,24,30,40,48,80,120,240\}$.
Let $P(n)$ be the product of all bi-unitary divisors of $n$. Define $Q_k(N)$ as the number of positive integers $1 \lt n \leq N$ such that $P(n)=n^k$. For example, $Q_2\left(10^2\right)=51$ and $Q_6\left(10^6\right)=6189$.
Find $\sum_{k=2}^{10}Q_k\left(10^{12}\right)$.