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Prime Factorization

Find the prime factors of any number. Also shows all divisors, divisor count, and divisor sum.

Enter a positive integer

Puzzle Tips

  • • Prime factors might be coordinate digits
  • • Divisor count/sum often appear in formulas
  • • Perfect squares, cubes have special factorizations
  • • Factorization helps with modular arithmetic

What is Prime Factorization?

Prime factorization is the process of finding which prime numbers multiply together to make a given number. Every integer greater than 1 can be uniquely expressed as a product of primes (Fundamental Theorem of Arithmetic).

How It Works

Algorithm

  1. Start with the smallest prime (2)
  2. Divide the number by 2 as many times as possible
  3. Move to the next prime and repeat
  4. Continue until the remaining number is 1

Example: 360

360 = 2 × 2 × 2 × 3 × 3 × 5 = 2³ × 3² × 5

Related Calculations

Divisor Count (τ)

If n = p₁^a₁ × p₂^a₂ × ..., then the number of divisors is (a₁+1) × (a₂+1) × ...

Divisor Sum (σ)

The sum of all divisors. A number is "perfect" if σ(n) - n = n (e.g., 6 = 1 + 2 + 3, 28 = 1 + 2 + 4 + 7 + 14).

In Geocaching Puzzles

Prime factorization appears in puzzles:

  • Factor extraction: Use specific factors as digits
  • Divisor puzzles: Count or sum divisors
  • Perfect numbers: 6, 28, 496 are special
  • Cryptography themes: RSA and similar puzzles