CREATE TABLE table_22371 ("Episode" TEXT, "Broadcast date" TEXT, "Run time" TEXT, "Viewers  ( in millions ) " TEXT, "Archive" TEXT)

How many viewers in millions watched the episode 23:55 minutes long?
SELECT "Viewers (in millions)" FROM table_22371 WHERE "Run time" = '23:55'
SELECT "Viewers (in millions)" FROM "table_22371" WHERE "Run time" = '23:55'