The list of all factors of 28 is :
{1, 2, 4, 7, 14, 28 },
We can get this list by listing all the numbers up to 28, and eliminate the nonfactors.
Of the factors in the above set, the primes are {2, 7}
So, the when we multiply the prime factors of 28 we get:
2*7=14
Answer: 14
