Which numbers is not a prime number

- Which of the following numbers is not a prime number
- Which of these numbers is not a prime number
- Which of the following numbers is not a prime number 79313
- Which one of the following numbers is not a prime number
- Which pair of numbers has hcf that is not a prime number
- Which of the following numbers are prime
- What is prime number in java
- How to know the number is prime or not