CREATE TABLE table_73638 ("Episode number Production number" CLOB, "Title" CLOB, "Original airdate" CLOB, "Rating/Share in Households" CLOB, "18\\u201349 Rating Live+SD / Live+7" CLOB, "Share" CLOB, "Live+SD Total viewers" CLOB, "Live+7 Day DVR Total viewers" CLOB)

When did the episode that had 3.69 million total viewers (Live and SD types combined) first air?
SELECT "Original airdate" FROM table_73638 WHERE "Live+SD Total viewers" = '3.69 million'
SELECT "Original airdate" FROM "table_73638" WHERE "Live+SD Total viewers" = '3.69 million'