Mneme is about 2 kilometres in diameter , and orbits Jupiter at an average distance of 21,427,000 km in 640.769 days , at an inclination of 149 Â to the ecliptic ( 148 Â to Jupiter 's equator ) with an eccentricity of 0.2214 . Mneme is about 2 kilometres in diameter , and orbits Jupiter at an average distance of 21,427 Mm in 640.769 days , at an inclination of 149 Â to the ecliptic ( 148 Â to Jupiter 's equator ) with an eccentricity of 0.2214 .