Today, the set of whole numbers is scattered in four entities: prime numbers, non-prime numbers (composites), but also ambiguous numbers zero and one. This is not really good analysis!
The concept and definition of an ultimate number (but also those of ultimate divisor) allows the classification of the set of whole numbers into four classes of entities with properties that are simultaneously interactive, unique and of progressive degree (from the class of ultimates) of complexity. Also, any whole number can only belong to one of these four classes and, simultaneously, must belong to one of these four classes: ultimate, raised, composite or mixed numbers.