Why is mine not runing

user_input = int(input("Enter a series of numbers and type exit to stop:>"))
numbers =[]
while user_input.lower()!= 'exit':
    while not user_input.isdigit():
        print('That is not number! Enter only numbers please:>')
        user_input = input('Try again please:>')
    numbers.append(int(user_input))
    user_input = input('Please enter next number:>')
total = 0
for number in numbers:
    total += number
print(f'Mean is {total/len(numbers)}')
print('sun(numbers)/len(numbers)')