Is 1921 a prime number?

The number 1921 has got 4 factors that are capable of dividing the number completely without leaving any remainder. Thus, the number 1921 is a non-prime number. The factors of 1921 include 1, 17, 113, and 1921.

For a number to be a prime number, it should follow the criterion of having no more than 2 factors: 1 and the number itself. Here, 1921 has more than 2 factors, hence making it a composite number.

Given below are a few ways that can be used to find prime or composite numbers.

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, it is to be checked whether the number is divisible by any numbers other than 1 and the number itself.

The counting divisors method for 1921 would simply be:

Divisors of 1921 = 1, 17, 113, 1921
Number of divisors = 4

The number 1921 can be considered composite.

In the divisibility test, we try to divide the number by any of the prime numbers. If we cannot, then it is considered a prime number.

In the divisibility method, a prime number only has 2 divisors, which are 1 and itself.

The divisors of 1921 are 1, 17, 113, and 1921.

Thus, 1921 consists of 4 factors that divide it completely without any remainder.
 

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

The list of prime numbers from 1900 to 2000 are:
1901, 1907, 1913, 1931, 1933, 1949, 1951, 1973, 1979, 1987, 1993, 1997, 1999

1921 is not present in the list, confirming it is not a prime number.
 

This method is only used for non-prime numbers or composite numbers. Since 1921 is a composite number, the prime factorization for 1921 is:

Factors of 1921 = 17 × 113
 

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

• Composite Number: A natural number greater than 1 that has more than two positive divisors. For example, 4, 6, and 9 are composite numbers.

• Factors: Numbers that divide a given number completely without leaving a remainder. For instance, the factors of 12 are 1, 2, 3, 4, 6, and 12.

• Divisibility Test: A method to check whether one number can be divided by another without leaving a remainder. It helps determine factors and identify prime numbers.

• Prime Factorization: Expressing a composite number as the product of its prime factors.