Factores primos

def factores(x):
    res = str(x) +" = "
    for i in range(2, x):
        while x%i==0:
            res += str(i) + "*"
            x/=i
    print(res[:-1])

x=2
while(x>0):
    x = int(input("Numero (0=salir)?"))
    factores(x)