This number is a prime.
1973 is the year Picasso died. [Stroup]
The smallest diagonal prime with distinct digits. (A diagonal prime is a prime of n^2 digits (n > 1) arranged left-right, top-down in a n-by-n matrix, where the diagonals are prime in each direction). [Loungrides]
If we examine the possible end digits of the first million primes, then "1" occurs the least, followed by "9", then "7", with "3" occurring the most. [Honaker]
Mr. Prime Beef has been serving Alaskan communities since 1973.
By luck, in 1973, a Bedouin — or nomadic Arab — guide named Eide Mariff came across a group of what looked like large, stone megaliths while crossing the Sahara. The discovery of Nabta Playa!