The numbers 2, 3, 4, and 6 are all whole numbers that fall within the category of natural numbers. They are used in counting and basic arithmetic. Each number has unique properties; for example, 2 is the smallest and the only even prime number, while 3 is the first odd prime number. In terms of their relationships, 4 is the square of 2, and 6 is the product of 2 and 3. Additionally, 6 is known as a perfect number because it is equal to the sum of its divisors: 1, 2, and 3.