Prime Numbers – Definition, Facts & Examples


The basic skill of classifying numbers is crucial for the math success of a child. Understanding the core concept of prime numbers helps them learn several high-level concepts and topics based on them. Prime numbers help form the understanding of composite numbers, prime factors, common factors, etc.

Prime Numbers - Definition, Facts & Examples

A child usually learns the concept of prime numbers at an elementary stage that develops their foundational understanding of concepts and vocabulary based on them. In higher grades, students need to apply their knowledge of prime numbers to build new concepts that are reliant on their prior knowledge. Thus, students must gain an in-depth understanding of prime numbers from an early stage.

Some students may find it challenging to learn these concepts later due to the lack of a basic understanding of prime numbers. It becomes a reason for concern as the topic is essential. It is difficult for students to solve complex problems based on factors, multiples, prime factorization, and prime numbers without a proper understanding of prime numbers.

What are Prime Numbers?

They are a subset of natural numbers greater than one, which is not a product of two smaller natural numbers. A prime number is divisible only by one and itself, which means that it has no divisor. One of the most exciting facts about prime numbers is their unique patterns and distribution among the natural numbers. Prime numbers are the set of numbers left over when we rewrite all numbers as their lowest possible combination of integers. When no further factoring can be done, all numbers leftover are primes. This property of being prime is called primality.

To verify if a number is a prime number, begin with dividing it by two and verify if you obtain a whole number. If you get a whole number, it can’t be a prime number. If you don’t get a whole number, try dividing it by prime numbers: 3, 5, 7, 11 (9 is divisible by 3), and so on. If the number is a prime number, it will not give a whole number when divisible by other prime numbers. For example, by dividing 11 with other prime numbers, you will not get a whole number, which means 11 is completely divisible by one and itself.

Facts About Prime Number

They are infinite and uniquely interesting. What makes primes so exciting is that the whole number line can be produced using nothing but primes. Let’s learn some exciting facts about prime numbers.

  • 2 is the only even prime number: Any other even number other than two is divisible by 2. So it can not be a prime number.
  • The first step to identifying a prime number is dividing it by 2: If you divide a number by two and obtain a whole number as a quotient, this number can’t be a prime number.
  • Zero and one are not considered Prime numbers: Both zero and one divide by only one positive integer, which is why they are not considered prime numbers.
  • They are used in protection from cybercrime: The encryption algorithms used in cryptographic techniques are based on two large prime numbers. Prime factorization is extremely difficult with huge values, and also, the unique factors of two large prime numbers are not that easy to decipher, which protects online data theft.

Application of Prime Numbers

It is majorly used in encryption algorithms. Cryptography is a practice of protecting digital information and communicating it through the use of codes. It is a useful technique practiced by computer programmers to build a unique code with numbers. Such kind of encoded information is quite convenient for computers to process and transfer securely.


The concept of prime numbers is the fundamental building block of various math concepts studied at different levels. As the child advances to higher grades, they need to study more complex topics based on them. Attaining the conceptual clarity of prime numbers can help them gain an in-depth understanding of these topics.


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