658 = 2 x 7 x 47.
658 is the number of triangles of any size contained in the triangle of side 13 on a triangular grid.
658 is the number of paths with n turns when light is reflected from seven glass plates, for n = 5.
A zero is located at the 658th position in the decimal expansion of pi.
658 is the sum of six positive cubes in exactly three ways.
PT-658, built in 1945, is a historic naval ship now being restored, in Portland, Ore.