Hi all again,

Now the problem is with Euler's Function. See:

1. Find all positive and integer $\displaystyle n$ such that $\displaystyle \varphi(n) = pq$, where p and q are prime.

2. Find all positive numbers $\displaystyle n$ such that $\displaystyle \varphi(n) = 8$

How do I approach these? Any tips are welcome.

Thanks in advance,