Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_2252745_1 (pop__km² VARCHAR, _number VARCHAR)
### Question:
When the # is 4, what is the pop./ km²?
### Answer:
SELECT pop__km² FROM table_2252745_1 WHERE _number = 4