CREATE TABLE table_30948 ("Episode" FLOAT, "Broadcast date" TEXT, "Guest ( s ) " TEXT, "Singer ( s ) " TEXT, "Comedian" TEXT, "Ratings" TEXT)

Name the guest for 1.64m ratings
SELECT "Guest(s)" FROM table_30948 WHERE "Ratings" = '1.64m'
SELECT "Guest(s)" FROM "table_30948" WHERE "Ratings" = '1.64m'