Many number base (radix) systems exist. Base 36 is not the largest base number, it comes from the number of digits (0-9 = 10) and the number of
letters in alphabet (A-Z = 26). You may add more symbols and create new number bases to count.
Base 10 (decimal) is used in arithmetic. Base 2 (binary), base 8 (octal), base 16 (hexadecimal) are generally used in computing.