Unsigned integer is 16-bit binary number, and its numerical range is: 0-6553 5;

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

Decimal value = 215+214+213+...+24+23+22+21+20 = 265438

=6553 5

So the maximum value can only be 6553 5.