Project Euler Problem3

Largest prime factor

Problem 3

The prime factors of 13195 are 5, 7, 13 and 29.

What is the largest prime factor of the number 600851475143 ?

The answer:

import math
def getLargestPrime(data):
    list = []
    i = 2
    while i <= math.sqrt(data):
    #while i <= data/2:
        if data%i == 0 :
            list.append(i)
            data = (int)(data/i)
            #i = 2
        else:
            i += 1
    list.append(data)
    return list

number = 600851475143
list = getLargestPrime(number)
print(list)
print(list[len(list) -1])

when the length of list equals 1, it is a composite number

From this problem, how to figure out whether a number is prime number。The solution is as follows:

def isPrime(data):
    i = 2
    while i<= math.sqrt(data):
        if data%i == 0:
            return False
        else:
            i += 1
    return True