56 is a composite number; it has factors other than 1 and itself. It is not a prime number.
The 8
factors of 56 are 1, 2, 4, 7, 8, 14, 28 and 56.
The
factor pairs of 56 are 1 x 56, 2 x 28, 4 x 14, and 7 x 8.
The
proper factors of 56 are 1, 2, 4, 7, 8, 14, and 28 or,
if the definition you are using excludes 1, they are 2, 4, 7, 8, 14, and 28.
The
prime factors of 56 are 2, 2, 2, and 7.
The 2
distinct prime factors (listing each prime factor only once) of 56 are 2 and 7.
The
prime factorization of 56 is 2 x 2 x 2 x 7 or, in index form (in other words, using exponents) 2
3 x 7.
NOTE: There cannot be common factors, a greatest common factor, or a least common multiple because "common" refers to factors or multiples that two or more numbers have in common.