In this task you will be given a list of numbers. You should remove any number that is not an integer (whole number). If every number is not an whole number then an empty list ("[]") should be returned. Otherwise, answer with the list of whole numbers separated by comma inside brackets.
[14.721, 87.717, -1, -20.693, -72, -66.851, 43.133, -57.046, -35.897, 15, 20.21]