Prime Number Checker
Test if a number is prime and list prime factors.
Prime Number Checker
Check whether an integer is prime or composite and view its complete factor list and prime factorization.
101 is a prime number! It has only two distinct factors: 1 and 101.
What is the Prime Number Checker and How Does It Work?
The Prime Number Checker tests whether a whole number is prime (divisible only by 1 and itself) or composite. If the number is composite, it lists its complete factors and prime factorization.
A number is checked for divisibility by every integer up to its square root; if none divide evenly, the number is prime.
No integer from 2 to 10 (≈√101) divides 101 evenly.
36 is divisible by several numbers besides 1 and itself; its prime factorization is 2² × 3².
Common Real-World Use Cases
Quickly verify whether a number is prime for homework, competitions, or coding exercises.
Explore prime numbers, which are foundational to encryption algorithms like RSA.
Check whether a numerator or denominator is prime as a step toward simplifying a fraction.
- 1Enter any positive integer.
- 2The calculator tests divisibility up to the square root of the number.
- 3View whether it is prime or composite, plus its full factor list and prime factorization if composite.
- •2 is the only even prime number - every other even number is divisible by 2 and therefore composite.
- •1 is neither prime nor composite by definition.
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