Problem 10 : Summation of primes

Problem Statement

The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17.

Find the sum of all the primes below two million.

Solution

def isPrime(n):
    if n < 2: return "Neither prime, nor composite"
    for i in range(2, int(n**0.5) + 1):
        if n % i == 0:
            return False
    return True

sum = 0
for i in range(2, 2000000):
    if isPrime(i):
        sum += i

print (sum)

Output

142913828922