Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_2252745_1 ( pop__km² VARCHAR, area__km²_ VARCHAR )

### Question ###
when the area (km ) is 22721, what is the pop./ km ?

### Accurate SQL ###

SELECT pop__km² FROM table_2252745_1 WHERE area__km²_ = 22721