Suppose that $P(x)$ is a monic quadratic polynomial satisfying $aP(a) = 20P(20) = 22P(22)$ for some integer $a\neq 20, 22$. Find the minimum possible positive value of $P(0)$.

[i]Proposed by Andrew Wu[/i]

(Note: wording changed from original to specify that $a \neq 20, 22$.)