Given three points $A$ $(10^{17}, 10^{17})$, $B$ $(3 \times 10^{17}, 3\times 10^{17})$ and $C$ $(X,0)$.

If $\angle ACB$ is the maximum possible, calculate $\lfloor\sqrt{X}\rfloor$,

where $\lfloor x \rfloor$ denotes the integer part of $x$.