What does $p^\alpha\| n$ mean? What does $p^\alpha\| n$ mean ? I saw this in Euler totient function,
$$\varphi(n)=\prod_{p^\alpha\| n}p^\alpha(p-1).$$

It means that $p^{\alpha}\mid n$ but $p^{\alpha+1}\nmid n$.
For example. $2^2\mid 12$ but $2^3\nmid 12$. Hence $2^2\|12$
