2000, there were 656,562 people, 265,649 households, and 141,590 families residing in the city (roughly comparable in size to San Francisco , Memphis , and Columbus ). The population density was 2,610.4 people per square mile (1,007.9/km²). There were 276,842 housing units at an average density of 1,100.7/sq mi (425.0/km²). The racial