It can be mathematically proven that the Catholic canon, with its 73 books, is superior to Orthodox or Protestant canons. Seven and three are both divine numbers, and 73 is the perfect number, according to Dr. Sheldon Cooper.
73 is the 21st prime number.
Its mirror, 37, is the 12th.
Its mirror, 21, is the product of 7 and 3.
73 is a palindrome in binary.
See? Math is both fun and theologically educational.