What are integers?
The set of integers is a set of numbers that includes all negative numbers, all positive numbers, and zero.
Examples of integers are -4, 7, 0, -17.
Note that 1/2 is not an integer, but rather a rational number.
So now that we know what integers are, we will answer our question.
Which number is an integer? -3, -4, 1, -5, 2, 4, 2/3
In fact, all of these are integers, except 2/3.
Hence, this is the answer.