I think you mean integer - whole, complete.
"Integer" comes from Latin and means "whole" or "intact."
a number consisting of an integer and a proper fraction.
The word integer is a noun.
That refers to a positive integer with more than two factors.
The Latin adjectives novus, novellus, recens and integer can all mean "new".
If you mean 21517 then it is an integer because it is a whole number. If you mean 2.1517 then it is not an integer because it is not a whole number.
It is an integer which is the successor to the integer 3.