What is the best classification of - 14 in the real number system?

Integers are the best classification.

Real number system is classified in 4 parts which are natural numbers, whole numbers, integer and rational numbers.

Natural numbers are 1,2,3,4,5,6, ...

Whole numbers are 0,1,2,3,4,5,6 ...

And integers are All negative and positive numbers.

Therefore - 14 best suits to integers.