The British boy band were put together by the music mogul on the 2010 series of the UK version of 'The X Factor' and claim Simon is so rich because he is very frugal with the cash he makes from his TV shows and pop acts.
Niall Horan quipped: ''Simon Cowell is tight. That's why he's so successful - he's able to keep his money to himself. We're paid in jelly beans.''
Despite Niall's comment, Simon recently paid all five members £2 million each, according to The Sun newspaper.
The boys - Niall, Zayn Malik, Harry Styles, Liam Payne and Louis Tomlinson - could be set to increase their earning potential even further by writing their own tracks just like music legends The Beatles.
Liam said: ''We did watch The Beatles' movie 'A Hard Day's Night' recently and it was funny to see things they did that are similar to us.''
Harry insists he and his bandmates - who are currently at number four in the Billboard Hot 100 singles chart with 'What Makes You Beautiful' - are working hard on new music to stay fresh.
He said: ''We're always writing on the road and in hotels and airports.
''We don't ever want our music to sound like a 40-year-old man in an office has written it and given it to us to perform.''