I interpret the number 666 as refering to the triple imperfection. 7 is the perfect number and 6 is falling short, and 777 is the most perfect number and 666 is the triply imperfect number. 666 is like imperfect cubed and 777 is like perfect cubed.

There is one thing I wonder about my interpretation though. Why doesn't the Bible have 6666 or 66666? Why only three 6 s? If 666 is imperfect then wouldn't 6666 be even more imperfect? And if 777 is triply perfect why not have 7777 quadruply perfect?

There are related questions like why are there only three spatial dimensions. Why not seven? I was reading something about how possibly three dimensional space actually is two dimensional and one dimension is emergent. So first there was three spatial dimensions, then Galileo and Einstein came and said with special relativity, no there's space-time with four dimensions, but then the holographic principle says since the entropy of a black hole increases from its surface area the anti De Sitter space has the bulk and the boundary and there's only two fundamental spatial dimensions and in total back to three dimensions. I read about these possibilities of there being only two spatial dimensions in Scientific American's recent black hole articles.