65,536 is a positive integer equal to 216 = 2222 = 42 = 2↑↑↑3. It is the largest power tower of 2's that can be expressed in a compact digital form (as 52 is an integer of 19,729 decimal digits). It is also the only nontrivial result of pentation expressible in compact digital form — 52 has 19,729 decimal digits, and 62 has well over a googol decimal digits.
It is found commonly in computer science, being the number of different values expressible in 16 bits (a short integer).
Its full name in English is "sixty-five thousand five hundred thirty-six."