Is 123456789 a prime number?

The number 123456789 has multiple factors that can divide the number completely without leaving any remainder. Thus, the number 123456789 is a non-prime number. The factors of 123456789 include 1, 3, 9, 13717421, 41152263, 123456789.

A number must meet the criteria of having only two factors: 1 and itself. Here, 123456789 has more than two factors, so it is a composite number. Given below are a few ways that can be used to determine if a number is prime or composite.

The different methods we can use to check if a number is a prime number are explained below:

1. Counting Divisors Method
2. Divisibility Test
3. Prime Number Chart
4. Prime Factorization
    

For the counting divisors method, we check if the number is divisible by any numbers other than 1 and the number itself. The counting divisors method for 123456789 would simply be: Divisors of 123456789 = 1, 3, 9, 13717421, 41152263, 123456789

Number of divisors = 6

The number 123456789 can be considered composite.
 

In the divisibility test, we try dividing the number by any of the prime numbers. If we can't, then it is considered a prime number. In the divisibility method, the prime number has only 2 divisors: 1 and itself. The divisors of 123456789 are 1, 3, 9, 13717421, 41152263, and 123456789. Thus, 123456789 has 6 factors that divide it completely without any remainder.
 

The prime number chart is a list of prime numbers starting from 2 to infinity.

The list of prime numbers under 100 is:

2, 3, 5, 7, 11, 13, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97.

123456789 is not present in the list; it is not a prime number.
 

This method is used for non-prime (composite) numbers. Since 123456789 is a composite number, the prime factorization of 123456789 is: Factors of 123456789 = 3 × 3 × 13717421

• Prime Number: A natural number greater than 1 that has exactly two distinct positive divisors: 1 and itself. For example, 2, 3, and 5 are prime numbers.

• Composite Number: A number that has more than two distinct divisors. Unlike a prime number, a composite number can be divided by numbers other than 1 and itself. For example, 4, 6, and 123456789 are composite numbers.

• Divisor: A number that divides another number completely without leaving a remainder. For example, the divisors of 6 are 1, 2, 3, and 6.

• Prime Factorization: The process of breaking down a composite number into prime numbers that multiply together to give the original number. For example, the prime factorization of 123456789 is 3 × 3 × 17 × 379721.

• Divisibility Test: A method used to determine whether a number is divisible by another number without performing the division. It checks if there is no remainder when dividing by prime numbers like 2, 3, 5, 7, etc.