Why does Sheldon say 73 is the perfect number?

I'm curious, why does Sheldon, the famous character from The Big Bang Theory, claim that 73 is the perfect number? What mathematical or personal significance does this number hold for him? Is there some hidden meaning behind his fascination with 73, or is it simply a quirky trait of his character? I'm eager to understand the reasoning behind his assertion and how it fits into the broader context of his personality and interests.