What are all the numbers that are odd but not prime?

Odd numbers that are not prime include all odd composite numbers. The smallest odd composite number is 9, followed by 15, 21, 25, 27, 33, 35, and so on. These numbers are odd because they are not divisible by 2, but they are not prime because they have divisors other than 1 and themselves. In general, any odd number that can be expressed as a product of two smaller odd integers is included in this category.