Range is too large Python

Question

I\'m trying to find the largest prime factor of the number x, Python gives me the error that the range is too large. I\'ve tried using x range but I get an OverflowError: Py

Answer 1

Very uneficient code, that's not the best way of getting dividers, I've done it with a for and range, but I can't execute it because of the long variables, so I decided to implement it with a for using a while, and increment a counter by myself.

For 32 bit int like 13195:

# The prime factors of 13195 are 5, 7, 13 and 29.
# What is the largest prime factor of the number 600851475143 ?

i = 13195
for j in xrange(2, i, 1):
    if i%j == 0:
        i = i/j
        print j

Good way for longer numbers:

# The prime factors of 13195 are 5, 7, 13 and 29.
# What is the largest prime factor of the number 600851475143 ?

i = 600851475143
j = 2

while i >= j:
    if i%j == 0:
        i = i/j
        print j
    j = j+1

The last prime is the last printed value.