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_name_24 (series_number VARCHAR, dvd_region_1_release_date VARCHAR, original_air_date VARCHAR, number_of_episodes VARCHAR)

### Question ###
How many series originally aired before 1999 with more than 7 episodes and a DVD Region 1 release date of 16 april 2013?

### Accurate SQL ###

SELECT COUNT(series_number) FROM table_name_24 WHERE original_air_date < 1999 AND number_of_episodes > 7 AND dvd_region_1_release_date = "16 april 2013"