Question

find the largest prime number which should be taken for testing whether it could be a factor of 620​

Answer 1

Answer:

I'm thinking the most efficient would be the following:

Find lowest prime number that divides cleanly

Check if result of division is prime

If not, find next lowest

Go to 2.

I'm basing this assumption on it being easier to calculate the small prime factors. Is this about right? What other approaches should I look into?

Edit: I've now realised that my approach is futile if there are more than 2 prime factors in play, since step 2 fails when the result is a product of two other primes, therefore a recursive algorithm is needed.