Reverse an integer without casting as a string

reverse_integer.py

def reverse_int(n: int) -> int:
  num, reverse_num, size_of_num = n, 0, -1
  copy = num

  while copy >= 1:
    copy //= 10
    size_of_num += 1

  while num >= 1:
    rem = num % 10
    reverse_num += (10 ** (size_of_num) * rem)
    size_of_num -= 1
    num //= 10
    
if __name__ == "__main__":
  reverse_int(12345)