If someone asked anda to guess how many Number Ones "American Idol" contestants have collected on the Billboard charts, what number would anda guess? 18? 80? 180? All would be wrong, and all would be under the actual count.

Bear in mind, Billboard compiles around 150 charts every week. There are charts for every format of music, for singles and albums, for sales and airplay. Including every national, domestic chart, the "American Idol" singers have racked up an astounding 257 No. 1's to date, and the number increases all the time. Kelly Clarkson has earned the most Number Ones, with a total of...