input: Write a python function to check if a given number or string is a palindrome.
  assert is_palindrome("racecar") == True
  assert is_palindrome(12321) == True
  assert is_palindrome("hello") == False
  assert is_palindrome(12345) == False
output: def is_palindrome(x):
      s = str(x)
      return s == s[::-1]