In literature as well, numbers and their meanings come up all the time. Four is seen as the number most representing nature (due to the four seasons, or the four elements) while three is a depiction of God, and seven (the perfect/lucky number) is such because its a combination of both four and three. As for humans, we're sometimes seen as number 5 or number 6...short perfection, but ruling over nature.
Speaking of nature, I heard it's going to get up to 40 degrees today, only to see the temperature drop and four inches of snow to fall later tonight. We could be looking at our fourth two-hour delay in the past two weeks..