596

596 = 2² x 149.

596 has a representation as a sum of two squares: 596 = 14² + 20².

596 is the maximum number of regions into which 34 lines divide the plane.

596 is the number of Hamiltonian cycles of a 4 x 9 rectangle graph.

596 was the code name for China's first nuclear weapons test, detonated Oct. 16, 1964.

Source: What's Special About This Number?