The prime factors of 80 are: 2 and 5.
http://wiki.answers.com/Q/What_are_the_Prime_facto...

80 is composite. It is 2 x 2 x 2 x 2 x 5. That's the prime factorization of 80.
http://www.chacha.com/question/whatisaprimefac...

The highest common factor of 48 64 and 80 is 16.
http://wiki.answers.com/Q/What_is_the_greatest_com...

Answer : The greatest common factor of 32 and 80 is 16. The common factors of 32 and 80 are 1, 2, 4, 8, and 16. Definition : A factor is a divisor  a number that will evenly divide
http://wiki.answers.com/Q/Gcf_for_32_and_80
