CREATE TABLE table_24558 ("No." FLOAT, "#" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "U.S. air date" TEXT, "Production code" TEXT, "U.S. viewers  ( million ) " TEXT)

What's the number of the episode seen by 2.24 million people in the US?
SELECT "#" FROM table_24558 WHERE "U.S. viewers (million)" = '2.24'
SELECT "#" FROM "table_24558" WHERE "U.S. viewers (million)" = '2.24'