CREATE TABLE table_23793770_1 (production_code INT, us_viewers__millions_ VARCHAR)

What the production code for the episode with 16.10 U.S. viewers?
SELECT MAX(production_code) FROM table_23793770_1 WHERE us_viewers__millions_ = "16.10"
SELECT MAX("production_code") FROM "table_23793770_1" WHERE "16.10" = "us_viewers__millions_"