This number is a prime.
The first occurrence of a twin prime pair (659, 661) one of which is strobogrammatic and the other one invertible when read on a calculator (7-segment digital display). Note that the latter when turned upside down becomes also the larger member of another twin prime pair (197, 199). [Beedassy]
0659, 2659, 3659, 5659, and 6659 are all primes. [Forouhati]
There is a binary star system in the constellation Cygnus consisting of a pair of K-type dwarf stars that orbit each other in a period of about 659 years.