欧拉计划(python) problem 3

Problem 3

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

What is the largest prime factor of the number 600851475143 ?

python code:

import math

sqrt=math.sqrt

def func(x):

m=int(sqrt(x)+1)

for i in range(2,m):

if x%i==0:

return 0

return 1

num=600851475143

n=sqrt(num)+1

n=int(n)

result=0

for i in range(2,n):

if num%i==0:

if func(i)==1:

result=i

print(result)

result : 6857

time: <1s