-40 is an even number.
-40 is a Harshad number, which means it is divisible by the sum of its digits (4 + 0 = 4, and -40 is divisible by 4).
In binary, -40 is represented as 1111111111111111111111111111111111111111111111111111111111011000.
In hex, -40 is represented as ffffffffffffffd8.