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_21146729_6 (series__number VARCHAR, original_airdate VARCHAR)

### Question ###
How  many of the  series # when the original airdate is september 25, 1967?

### Accurate SQL ###

SELECT COUNT(series__number) FROM table_21146729_6 WHERE original_airdate = "September 25, 1967"