IT

Free Online Number Theory Calculators | Prime, LCM, GCD & Modular Arithmetic

Comprehensive collection of free online number theory calculators for students, mathematicians, and developers.

Explore prime numbers, factorization, divisibility, modular arithmetic, and other number properties instantly.

Number Theory Calculators
Explore properties and relationships of numbers
Prime Number Checker
Check if a number is prime and see its factors. A prime number has exactly two distinct positive divisors.

Enter any positive whole number (up to 1,000,000)

Result

Enter a number above to check if it's prime

How to Use Our Number Theory Calculators

Our number theory calculators provide instant solutions for various mathematical problems. Follow these simple steps:

1

Select the specific number theory calculator you need from the dropdown menu

2

Enter the required numerical values in the input fields

3

Click calculate or press enter to see the results

4

Review the detailed mathematical solution displayed

5

Use the results for your studies, projects, or mathematical research

Key Features of Our Number Theory Calculators

Multiple calculation methods including prime checking, factorization, and divisibility tests
Real-time calculation with instant results for quick problem-solving
Detailed step-by-step solutions showing the mathematical process
Support for various number theory operations (primes, factors, moduli, etc.)
Accurate results based on proven mathematical algorithms and theorems
Mobile-friendly responsive design for use on any device

Examples You Can Try

Prime Number Checker

Check if a number is prime. Try entering 17, 23, or 97 to see they're prime, or 15, 21 to see they're composite.

Prime Factorization Calculator

Find prime factors of a number. Enter 60 to get 2² × 3 × 5, or 100 to get 2² × 5².

Divisibility Checker

Verify if one number divides another evenly. Check if 144 is divisible by 12 (yes), or if 99 is divisible by 7 (no).

LCM Calculator

Calculate the least common multiple. Find LCM(12, 18) to get 36, or LCM(7, 11) to get 77.

Common Use Cases

Students & Education

Learn and practice number theory concepts, verify homework solutions, and explore mathematical properties

Cryptography & Security

Analyze prime numbers, modular inverses, and number properties essential for cryptographic algorithms

Computer Science

Solve algorithmic problems involving primes, factors, and number-theoretic functions

Mathematical Research

Investigate number patterns, verify conjectures, and perform exploratory number theory research

Understanding Number Theory Fundamentals

Number theory is a branch of pure mathematics devoted primarily to the study of integers and integer-valued functions. It explores fundamental properties of whole numbers and their relationships, forming the basis for much of modern cryptography and computer science.

Prime numbers are natural numbers greater than 1 that have no positive divisors other than 1 and themselves. Prime factorization is the decomposition of a composite number into a product of prime numbers, unique up to the order of factors according to the fundamental theorem of arithmetic.

The least common multiple (LCM) of two integers is the smallest positive integer that is divisible by both numbers. Modular arithmetic involves performing operations in a number system where numbers 'wrap around' upon reaching a certain value, called the modulus. The modular inverse of a number 'a' modulo 'm' is a number 'x' such that (a × x) ≡ 1 (mod m), if such x exists.

Common Mistakes and Tips

Mistake

Confusing prime numbers with irreducible polynomials or composite numbers

Tip

Remember that 1 is not considered prime, and all primes greater than 2 are odd (except 2 itself)

Mistake

Incorrectly assuming that LCM(a,b) equals a×b without checking for common factors

Tip

Use the relationship LCM(a,b) = (a×b) / GCD(a,b) for accurate calculations

Mistake

Forgetting that modular inverse doesn't exist when the number and modulus share common factors

Tip

A modular inverse exists only when the number and modulus are coprime (their GCD is 1)

Mistake

Using inefficient algorithms for primality testing of large numbers

Tip

Our calculator uses optimized methods to determine primality quickly and accurately

Frequently Asked Questions

Are these number theory calculators free to use?

Yes, all our number theory calculators are completely free to use with no hidden charges or registration requirements. Simply visit the tool, enter your values, and get instant results.

How accurate are the number theory calculations?

Our calculators use precise mathematical algorithms and proven theorems to ensure maximum accuracy. Results are computed using exact arithmetic where possible and follow standard mathematical conventions.

Do I need to install any software?

No, our number theory calculators run entirely in your web browser. There's no need to download, install, or configure any software. Just access them online from any device with internet connection.

Can I use these calculators on mobile devices?

Absolutely! All our number theory tools are designed with responsive layouts that work seamlessly on smartphones, tablets, and desktop computers.

What types of number theory calculations can I perform?

Our collection includes calculators for prime numbers, prime factorization, divisibility testing, LCM computation, modular inverses, and various other number-theoretic functions and properties.

Is my data secure when using these calculators?

Yes, all calculations happen locally in your browser. We don't store, collect, or transmit your input data to any external servers, ensuring complete privacy and security.

Can I calculate with very large numbers?

Our calculators support reasonably large integers, though extremely large numbers may be subject to browser JavaScript limitations. For most practical number theory applications, our tools will work effectively.