If its sentient then it pretty resourceful. I really hate when Sci-Fi pulls the trope of the humans being the best innovators and designers.

Also even if he does have that many planets, which I doubt, there probably counting worlds that are just backwater or only have a single outpost. When I say 20 Million im only taking about worlds that are fully developed, there is many more that are claimed but aren't. Its like the AIF is counting oranges and apples as apart of the count of planets but Equestria is only counting oranges.