What type of number has no factors other than 1 and itself?

More Questions:

What off-road endurance race is named after the African capital where it usually ends?

A light aircraft without an engine is called a what?

What was the original flavor of the cream in Twinkies?

What kind of wine takes its name from the Spanish town of Jerez, where it is made?

What duo was responsible for launching Wikipedia in 2001?

What literary work inspired the Beatles" "Tomorrow Never Knows" song?

What Grimm's fairy-tale character is named for a vegetable craved by her pregnant mother?

Which South American country's name is literally "Land of Silver'

What is added to bread to make it swell?

What is January's birthstone?

Who was The Black Adder?

What Broadway Musical is based off the opera "La Bohem"?

What year did the Franco-Prussian War begin?

Who performed "The Wall" by the Berlin Wall?

In what decade did Toronto surpass Montreal as the most populous city in Canada?