
Originally Posted by
ciaban
you are all wrong. 73 is the perfect number
it's the 21st prime number, it's mirror is 37 which is the 12th prime number the mirror of 21
21 is a product of multiplying hang on to your hats 7 & 3. Did I lie? no it's the perfect number.
And in binary it's a palindrome 1001001, also 21( which 73 is the 21st prime number) is a palindrome 10101
It's square root is 8.544 which if added together 8+5+4+4=21 the product of 7&3
In Base 5 the smallest sum with a composite set of digits is 73
73 is the only only prime repunit in base 8
also, 73 and it's mirror 37 are both sexy primes twice over!
it's a star number
it's the 8th pair of prime numbers along side 71
It's the perfect number!