971

This number is a prime.

The only prime in the following alphametic:

       UK 
      USA 
   + USSR
   -------- 
    ABOMB.

The largest prime containing only odd digits, in decreasing order. [Hasler]

The largest prime formed from the concatenation of one-digit composite number, one-digit prime number, and one-digit number that is neither prime nor composite. [Wesolowski]

The smallest emirp p which taken together with the pth prime, also an emirp (7649), forms yet another emirp (9717649). [Beedassy]

The largest prime (emirp) formed from the complementary digits of the single-digit powers of 3, (3^0=1, 3^1=3, 3^2=9), i.e., 9, 7, 1. [Loungrides]

King Solomon's reign began circa 971 BCE. [Jewish Encyclopedia]

Joseph Asscher of Amsterdam gained fame for cutting the famous 971 carat Excelsior rough diamond. [Haynes]