Project Euler Question 3 Help

Question

I\'m trying to work through Project Euler and I\'m hitting a barrier on problem 03. I have an algorithm that works for smaller numbers, but problem 3 uses a very, very large

Answer 1

For starters, instead of beginning your search at n / 2, start it at the square root of n. You'll get half of the factors, the other half being their complement.

eg:

n = 27
start at floor(sqrt(27)) = 5
is 5 a factor? no
is 4 a factor? no
is 3 a factor? yes. 27 / 3 = 9. 9 is also a factor.
is 2 a factor? no.
factors are 3 and 9.