question: How many codes have a density of 621.68, and a Land area (hectares) larger than 75.28?
answer: SELECT SUM(code) FROM table_name_24 WHERE density__inh_km²_ = 621.68 AND land_area__hectares_ > 75.28
context: CREATE TABLE table_name_24 (code INTEGER, density__inh_km²_ VARCHAR, land_area__hectares_ VARCHAR)