Is 1 a Prime Number

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What is a Prime Number?

Before knowing if 1 is a prime number or not, let us understand what is a prime number. A prime number may be an integer greater than 1 whose only factors are 1 and itself. An element may be an integer which will be divided evenly into another number. The few prime numbers are 2, 3, 5, 7, 11, 13, 17, 19, 23, 29 and so on. Numbers that have more than two factors are called composite numbers. The number 1 is neither prime nor composite.

For every prime p, there exists a major number p' such p' is bigger than p. This proof, which was demonstrated in the past by the Greek mathematician Euclid, validates the concept that there's no "largest" prime. As the set of natural numbers N = {1, 2, 3, ...} proceeds, prime numbers are generally subsided frequently and are harder to seek out in a reasonable amount of your time. As of this writing, the most important known prime has 24,862,048 digits. It was discovered in 2018 by Patrick Laroche of the good Internet Mersenne Prime Search (GIMPS).

Properties of Prime Numbers

  • Every number that's greater than 1 is often divided by a minimum of one prime.

  • Every even positive integer was greater than the amount 2 is often expressed because of the sum of two primes.

List of Prime Numbers


Number of Prime Numbers

List of Prime Numbers From 1 to 1000

1 to 100

Total of 25 numbers

2, 3, 5, 7, 11, 13, 17, 23, 19, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97


Total of 21 numbers

101, 103, 107, 109, 113, 131, 127, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199

Is 1 a Prime Number?

Number 1 has positive divisors for 1 and itself. consistent with the definition of a  prime number. Any number having only two positive divisors is referred to as prime numbers. So, is 1 a prime number or not? Is 1 a prime or composite number?

The answer to the present question is: No, 1 isn't a major prime number and it's not a composite number!

Lesson Summary:

Is 1 a prime number?

No, it is not a prime number.

Is 1 a composite number?

No, it is not a composite number.

What are the factors of 1?

There is only one factor for 1 which is 1.

Why is 1 not a Prime Number?

The answer to Why 1 is not a Prime Number is present in the definition for the prime numbers itself. For a number to be called the prime number, it must have only two of the positive factors. Now, for 1, the number of positive divisors or factors is only one that is 1 itself. So, this is why 1 is not a prime number here.

Note: 2 is the smallest number that satisfies the definition for the prime numbers.

What is 1 Called and if One is a Prime Number or Not?

Number 1 is not the prime nor the composite number. In mathematics, there are many categories of numbers where the number 1 falls. So, 1 can also be called by any of the following numbers:

  • A natural number

  • An odd number

  • A rational number

  • A positive integer

  • A whole number

Why is 1 Not a Composite Number?

The answer to this is present in the definition for the composite numbers. According to the definition, a composite number is a natural number with more than two positive factors. But, 1 has only 1 factor i.e. 1 itself. So, one is not a composite number.

Solved Examples

Question 1: Which one of the following is a prime number?

  • 13

  •  6

  • 10

  • 4

Answer: 13 is a prime number because 13 has only two factors that are 13 and 1.

Question 2: Which one of the following is a prime number?

  • 3

  • 16

  • 20

  • 15

Answer: 3 is a prime number because 3 has only two factors that are 3 and 1.

Question 3: Which one of the following is a prime number?

  • 12

  • 43

  • 90

  • 15

Answer: 43 is a prime number because 43 has only two factors that are 43 and 1.

Question 4: Which one of the following is a prime number?

  • 21

  • 63

  • 53

  • 15

Answer: 53 is a prime number because 53 has only two factors that are 53 and 1.

FAQ (Frequently Asked Questions)

Question 1. What is 1 Called if it is not Prime?

Answer: A prime number can be a number which is greater than 1 that's not the product for two smaller natural numbers. A number greater than 1 that's not prime is named a number.

Question 2. What is Number 1 Called?

Answer: 1 (one, also called unit, and unity) may be a number and a numerical digit that used to represent that number in numerals. It represents one entity, the unit of counting or measurement. For instance, a line segment of unit length may be a line segment of length 1. 1 is the first and smallest positive integer.

Question 3. Who Invented 1?

Answer: As per Hindu & Arabic numerals, the set of the 10 symbols are - 1, 2, 3, 4, 5, 6, 7, 8, 9, 0 - They represent the numbers within the decimal numeration system. They were introduced to the whole of Europe with the help of the writings of the Middle Eastern mathematicians, especially the al-Khwarizmi and the al-Kindi, about the 12th century.

Question 4. Is 1 a Prime Number or Co-Prime Number?

Answer: The numbers 1 and −1 are the sole integers coprime with every integer, and that they are the sole integers that are coprime with 0. Variety of conditions are like a and b being coprime: No prime divides both a and b.