2, 3 and 5.
Once all the prime factors of a number have been found, the number of factors the number has and what they are can be found. I'd be finding the prime factors first before finding all the factors of a number, so I'd rather find all the prime factors as it means I can stop before I have to do more work in finding all the factors.
All numbers have factors. Some factors are prime numbers. These are known as prime factors. The set of prime factors is a subset of the set of factors for any given number.
You cannot list all the potential prime factors. Any prime number can be a prime factor. There are an infinite number of prime numbers, so there are an infinite number of potential prime factors. If given a specific number, the prime factors for it can be listed.
All numbers have factors. Some factors are prime numbers, some are composite numbers, one is neither. When finding the factors of a number, you find all the factors. The prime factorization is a multiplication string of just prime factors that will total the given number.
All prime numbers have only 2 factors. A prime number has 1 and itself as its only factors.
All prime squares have three factors.
Not to overstate the obvious, but factor lists are lists of factors. Once you have found all the factors of a number, it is customary to list them from least to greatest.
There is no such number. All numbers have a common factor of 1, which is neither prime nor composite. Any composite number can be reduced to its prime factors.
The number 1 and the prime number itself.
As 23 is a prime number, it has only two factors, the number one and itself. The factors of 23 are: 1 23 The prime factors are: 23 is a prime number.
All numbers that only have one and itself as factors are prime. Therefore, to tell if a number is prime simply find it's factors. If it has more than two factors than it is not a prime number, it is composite.