What term describes a number whose only factors are 1 and itself?

The term that describes a number whose only factors are 1 and itself is "prime." A prime number is defined as a natural number greater than 1 that cannot be formed by multiplying two smaller natural numbers. In other words, it has exactly two distinct positive divisors: 1 and the number itself.

For example, the number 7 is prime because the only numbers that divide it evenly are 1 and 7. Conversely, composite numbers have more than two factors. For instance, the number 6 is composite because it can be divided by 1, 2, 3, and 6. Odd and even numbers refer to the divisibility of a number by 2. An odd number is not divisible by 2, while an even number is. While primes can be either odd (like 3, 5, 7) or even (the only even prime number is 2), the characteristic of being prime is specifically related to the number of its factors. Thus, the definition of prime stands alone in this context and is indeed the correct answer.