The Big Bang Theory: 21 Easter Eggs You Probably Missed
8. Sheldon's Favourite Number 73
You may have seen 73 dotted around the show often, why? Because it's Sheldon Cooper's favourite number of course, with a string of T-shirts bearing the number. But where did the obsession come from?
Well, 1973 is actually the year actor Jim Parsons was born, and in the 73rd episode of the show The Alien Parasite Hypothesis, Sheldon explains: "The best number is 73. Why? 73 is the 21st prime number. Its mirror, 37, is the 12th [prime number] and its mirror, 21, is the product of multiplying 7 and 3...and in binary 73 is a palindrome, 1001001, which backwards is 1001001." Of course, how obvious...