Which president was nicknamed "Silent Cal"?

Which president was nicknamed "Old Rough and Ready"? Which president was nicknamed "The Little Magician"? Which president was nicknamed "Tippecanoe" after an 1811 battle? Which president was nicknamed "His Accidency" after taking office on a president's death? Which president was nicknamed "Ike"? Which president was nicknamed "The Gipper," from one of his movie roles? Which president was nicknamed "The Great Communicator"? Which president was nicknamed "Dubya"?