# 397

This number is a prime.

The Carillon Residences North Tower in Miami Beach is 397 feet tall.

Conjectured to be the largest prime that can be represented uniquely as the sum of three positive squares (3^2 + 8^2 + 18^2). [Noe]

The prime that splits into a prime pair (3, 97) with sum one
hundred and *minimal* product (3*97=291). Note
that the sum-product concatenation 100291 is prime, and
that 397 is a left-truncatable prime, just like its
counterpart prime 5347 that splits into two complementary
primes (53, 47) also summing up to a hundred, but with
*maximum* product (53*47=2491). The reversal of
whose sum-product concatenation however being also prime
(1942001). [Beedassy]

Iranian grandmaster Morteza Mahjoob won 397 (of his 500) chess games to break the Guinness Book World Record for the most number of simultaneous matches in August 2009.

397 and 401 are the largest pair of consecutive primes that together have no duplicate digits. [Gaydos]

The smallest non-palindromic balanced prime in base 2. [Nie]