620 is a composite number because it has factors other than 1 and itself. It is not a prime number. The 12 factors of 620 are 1, 2, 4, 5, 10, 20, 31, 62, 124, 155, 310, and 620. The proper factors of 620 are 1, 2, 4, 5, 10, 20, 31, 62, 124, 155, and 310 or, if the definition you are using excludes 1, they are 2, 4, 5, 10, 20, 31, 62, 124, 155, and 310. The prime factors of 620 are 2, 2, 5, and 31. Note: There is repetition of these factors, so if the prime factors are being listed instead of the prime factorization, usually only the distinct prime factors are listed. The 3 distinct prime factors (listing each prime factor only once) of 620 are 2, 5, and 31. The prime factorization of 620 is 2 x 2 x 5 x 31 or, in index form (in other words, using exponents), 2 2 x 5 x 31. 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.
