This is very inefficient algorithm to solve the problem. It takes Python more than 5 minutes to solve the problem with the number given

Euler Project #3.py

import unittest
from math import sqrt
def isPrime(i):
    if (i == 2 or i == 3):
        return True
    else:
        for j in range(3, int(sqrt(i)+1)):
            if ( i  % j == 0):
                return False
    return True

def FindLargestPrimeFactor(number):
    '''
    Input: a number
    Output: The largest prime factor of the number
    Essentially checking for if all possible integers less then sqrt(number) are prime or not, then
    return the largest one found.
    ''' 
    max = 0
    for i in range(3,int(sqrt(number)+1)):
        if isPrime(i):
            if (number % i == 0):
                max = i
    return max
    
def FindLargestPrimeFactor_2(number):
    '''
    
    '''

class Test(unittest.TestCase):
    def test_FindLargestPrimeFactor(self):
        self.assertEqual(FindLargestPrimeFactor(13195),29)

if __name__ == '__main__':
    unittest.main(exit=False)
    print(FindLargestPrimeFactor(600851475143))