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_64 ( viewers__m_ VARCHAR, episode VARCHAR )

### Question ###
What Viewers (m) has an Episode of 40 days?

### Accurate SQL ###

SELECT viewers__m_ FROM table_name_64 WHERE episode = "40 days"