Then that number is probably wrong, but you asked me where that number came from, and I told you.
“A million years” seems intended to be different from “1,000,000 years” in a way similar to how “a year” is different from “365 days”.
“A million years” seems intended to be different from “1,000,000 years” in a way similar to how “a year” is different from “365 days”.