소수 찾기 - [파이썬]

from itertools import permutations
import math

def is_prime(x):    #소수 판별 함수
    for i in range(2, int(x**0.5)+1):
        if x % i == 0:
            return False
    return True

def solution(numbers):
    answer = 0
    n = list(numbers)
    a = []
    for i in range(1, len(n) + 1):
        a += list(permutations(n, i))

    b = []
    for j in a:
        b.append(int(''.join(j)))
    b = list(set(b))

    for k in b:
        if k <= 1:
            continue
        elif is_prime(k):
            answer += 1

    return answer

numbers = "17"
print(solution(numbers))