16, 81, 625
Factors are whole numbers that divide exactly into a whole number. These numbers have no remainder. Primes, on the other hand, have exactly two factors which are 1 and itself.
A prime number is a positive integer that has exactly two different factors: 1 and itself. This is why 1 is not a prime number: it has the factors 1 and itself, but they are the same - it does not have exactly two different factors.
the proper factors are the factors of a number not including the number itself, or 1.
Any of its factors including itself
Any of its factors including itself
Any of its factors including itself
Any of its factors including itself
Any of its factors including itself
Any of its factors including itself.
Any of its factors including itself
Any of its factors including itself
Any of its factors including itself