A Friday Puzzle

To end the week, a simple-to-state puzzle that I've re-written/adapted from an old Henry Dudeney volume:

In the course of a year, the cats (and there are more than one) on Mr. Schlobotnik's farm killed 999,919 mice. If every cat killed exactly the same number of mice (and more than 1), then how many cats reside on the farm, given that the total number of cats is LESS than the number of mice killed per cat?
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Answer:
there were 991 cats, who each killed 1009 mice