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_221398_1 (pop_density___km²_ VARCHAR, number_in_map VARCHAR)
### Question:
How many prefectures have a population density of 16 people/kilometers squared?
### Answer:
SELECT COUNT(pop_density___km²_) FROM table_221398_1 WHERE number_in_map = "16"