Check if a number is prime, find prime factorization, or list primes in a range
Enter a number to check or find primes
Calculate the Greatest Common Divisor and Least Common Multiple
Generate Fibonacci numbers by count or up to a maximum value
Add, subtract, multiply, and divide fractions with simplified results
Full-featured scientific calculator with trigonometry, logarithms, and history
Prime Number Checker is a free online tool that determines whether a number is prime, shows its prime factorization, lists all factors, and can find all prime numbers within a given range. A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself. This tool is useful for math students, programmers, and anyone interested in number theory. All calculations happen in your browser.