Puzzle "first 10-digit prime found in consecutive digits of e"

first 10-digit prime found in consecutive digits of e

import math


def get_e():
    from decimal import Decimal, getcontext
    getcontext().prec = 200 # improve precision
    e, f, n = Decimal(0), Decimal(1), Decimal(1)
    while True:
        old_e = e
        e += Decimal(1) / f
        if e == old_e:
            break
        f *= n
        n += Decimal(1)
    return Decimal(e)


def is_prime(n):
    if n % 2 == 0 and n>2:
        return False
    return all(n % i for i in xrange(3, int(math.sqrt(n)) + 1, 2))


def find_prime(number=get_e(), n_prime_len=10):
    if not isinstance(number, str):
        s = str(number)[2:]
    for i,_ in enumerate(s):
        number = int(s[i:i+n_prime_len])
        if is_prime(number):
            print("Found prime number {} at index {}".format(i, number))
            break

if __name__ == '__main__':
    find_prime()