Table schema:
CREATE TABLE table_name_41 (subregion VARCHAR, no_p VARCHAR, pop_area__1_km²_ VARCHAR)

Question: Which Subregion has a No P. of 4, and a Pop/Area (1/km²) of 534?
SQL: SELECT subregion FROM table_name_41 WHERE no_p = 4 AND pop_area__1_km²_ = 534