def euler():
num=600851475143
tl = primes_sieve(int(sqrt(num)))
best=1
for x in tl:
if isInt(num/float(x)) and x>best:
best=x
print "Euler 3 answer: %d" %best
def euler():
ans = primes_sieve(2000000)
print("Euler 10 answer: %d") %sum(ans)
