CREATE TABLE table_22261877_1 (us_viewers__million_ VARCHAR, production_code VARCHAR)

How many viewers in millions watched the episode with the production code 6acx16?
SELECT us_viewers__million_ FROM table_22261877_1 WHERE production_code = "6ACX16"
SELECT "us_viewers__million_" FROM "table_22261877_1" WHERE "6ACX16" = "production_code"