Let $n$ be a composite number so that it has at most one prime factor such that $p \leq \sqrt{n}$. Find all ways how you can factor $n$ and give examples.
My work:
We know that if $n$ is composite, there has to be at least one prime factor with such property. We also can deduce that for any other prime factors of $n$ - lets call them $q_i$ there can be at most one of them because $q_i^2 > n$. So the different ways you could factor $n$ I came up with are
1) $n=p^k$ - for example $16=2^4$. 2) $n=p^k \cdot q$ - for example $44 = 2^2 \cdot 11$. 3) $n=p\cdot q$ - for example $22 = 2 \cdot 11$.
Are there any ways that I am missing?
You already found out that at most one prime factor can exceed $\sqrt{n}$ (this is true for every positive integer $n$). Moreover, we know that we must have exactly one prime factor $p\le \sqrt{n}$ (Because of the mentioned condition).
If no prime factor exceeeds $\sqrt{n}$, then we must have a prime power.
If one prime factor exceeds $\sqrt{n}$, the exponent corresponding to this prime must be $1$, so we must have a prime power multiplied with this prime.
Hence , you did not overlook examples.