Significance of number 73 from Big Bang Theory

On the Show, Sheldon’s favorite number is 73, because 73 is the 21st prime number. Its mirror, 37, is the 12th and its mirror, 21, is the product of multiplying 7 and 3. In binary 73 is a palindrome, 1001001, which backwards is 1001001. In real life, Jim Parsons, who plays Sheldon was born in 1973. (Courtesy: Facebook)