A base 16 system is called hexadecimal. The digits most commonly used to represent it are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F. A digit in hexadecimal corresponds to a string of four digits in binary. 16 is the fourth square number (between 9 and 25) and the second fourth power (between 1 and 81). It is the only number that is equal to both x^y and y^x where both are positive integers.
It is the only integer that can be expressed as both xy and yx where x and y are distinct integers.
In googology Edit
In Greek-based number-naming systems, is associated with prefix "hexadeka-", and with prefix "sexdec-" in Latin systems.
It can be named trwo with the -wo series.
It can be named "garfour" with the gar- prefix.