1) The Scriptures say he has "myriads on myriads" of angels, and a myriad is 10,000 - so he must have a grip.
2) The Scriptures say when Satan was thrown out of heaven, a "third" of them were cast out with him. A "third" in the Bible didn't always mean a literal fraction of 1/3, but could mean "a significant amount" of something.