Please help, for I am not formally trained in higher math.

What mathematical formula can quickly find the lowest, whole-number factors
to any number? For instance, I would really like to quickly find the lowest
factors to this series of numbers: 3, 7, 9, 11, 13, 17, 19, 21, 23, 27, 29.

Clearly, those that are prime numbers will not have any other lowest factor
than one (1) x itself. What about the quickest way to find the lowest factors
to, say, 27, other than 1 x 27? Obviously, there's only 3 x 9. But, how can I
calculate that specific set of factors (3 x 7) in one fell swoop?

Your answer will be really valuable to me. Thank you sooooooooooooo much!!!