➗ Math & Statistics Calculators › Algebra & Numbers

Prime Factorization & Factor Tree Calculator

Find prime factors, exponential prime decomposition, all positive divisors, and factor count.

Prime Factors — interactive calculator, computed instantly in your browser.

📚 Authoritative Educational Guide

Prime Factorization & Factor Tree Guide: Sieve of Eratosthenes

Prime factorization decomposes a composite integer into a product of prime numbers (numbers greater than 1 that have no positive divisors other than 1 and themselves). Prime numbers serve as the fundamental "atoms" of all number theory and modern cryptography (such as RSA encryption).

1. Canonical Exponential Form

Any positive integer $n$ can be uniquely expressed in canonical prime factorization form:

n = p_1^{a_1} \times p_2^{a_2} \times \dots \times p_k^{a_k}

For example, $360 = 2^3 \times 3^2 \times 5^1$.

2. Divisor Count & Sum Functions

From the prime factorization, you can directly determine the total count of positive divisors $\sigma_0(n)$:

\sigma_0(n) = (a_1 + 1)(a_2 + 1)\dots(a_k + 1)

For $360 = 2^3 \times 3^2 \times 5^1$, total divisors = $(3+1)(2+1)(1+1) = 4 \times 3 \times 2 = \mathbf{24\text{ divisors}}$.

🔗 Number Theory & Prime Decompositions

The Fundamental Theorem of Arithmetic establishes that every integer has a unique prime factorization. Browse our ➗ Math & Statistics Hub for number theory tools.

Find Greatest Common Factors or calculate exponential powers with the tools below.

Frequently Asked Questions (Prime Factors)

Why is 1 neither prime nor composite?

By mathematical definition, 1 is excluded from the primes to preserve the uniqueness of the Fundamental Theorem of Arithmetic. If 1 were prime, factorizations would not be unique (e.g. $6 = 2 \times 3 = 1 \times 2 \times 3 = 1^5 \times 2 \times 3$).

How does RSA encryption rely on prime factorization?

RSA encryption pairs public keys made from multiplying two massive 1024-bit prime numbers. While multiplying two primes takes milliseconds, finding the prime factors of the resulting product takes supercomputers billions of years.