How to check if the value (not the field type) is an integer?

I know about the 'is_int' filter, however, the 'is_int' filter checks if the field type is an integer, not the actual value.

I have my field type set to decimal because it stores both decimals and/or integers. As a result, I have no way of checking if the value itself is an integer or not because the 'is_int' function always returns 'false'