Why this code in python gives this error? TypeError: object of type 'int' has no len() but i'm calling it on a list

Question

此代码抛出以下错误：

while len(digits) > 1:
TypeError: object of type 'int' has no len()

但我的可变数字是一个列表，对吗？我想一定有我不明白的列表理解

def per(n):

    if len(str(n)) == 1:
        return n

    else:
        digits = [int(i) for i in str(n)]

        count = 1
        while len(digits) > 1: # TypeError:object of type 'int' has no len()

            result = 1
            for j in digits:
                result *= j
        
            digits = result
            count += 1

    return count

print(per(716235))

Answer 1

def per(n):

    if len(str(n)) == 1:
        return n

    else:
        digits = [int(i) for i in str(n)]

        count = 1
        while len(digits) > 1:

            result = 1
            for j in digits:
                result *= j
        
            digits = result # <-------- Right here you are setting digits
                            # <-------- as result which is an integer
            count += 1

    return count

print(per(716235))