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_73638 ( "Episode number Production number" text, "Title" text, "Original airdate" text, "Rating/Share in Households" text, "18\u201349 Rating Live+SD / Live+7" text, "Share" text, "Live+SD Total viewers" text, "Live+7 Day DVR Total viewers" text )

### Question ###
When did the episode that had 3.69 million total viewers (Live and SD types combined) first air?

### Accurate SQL ###

SELECT "Original airdate" FROM table_73638 WHERE "Live+SD Total viewers" = '3.69 million'