1. Composite number refers to the number that can be divided by other numbers (except 0) in addition to 1 and itself in an integer greater than 1. The opposite is prime number, and 1 is neither a prime number nor a composite number. The smallest composite number is 4. Among them, perfect number and blind date number are based on it.
2. The method of classifying composite numbers is to calculate the number of its factors. All composite numbers have at least three factors. The square of a prime number has a factor of. If a number has more factors than its smaller integers, it is called a high composite number. In addition, the number of factors of perfect square numbers is odd, while other composite numbers are even.
