SpeedDrain
Primality Test · Prime Factorization · Divisors List · Neighboring Primes

Prime Number Checker

Check if any number is prime, decompose composite integers into prime factors, list every divisor, and find neighboring primes.

Presets:

Fast deterministic Miller-Rabin test supports values up to 2⁵³ - 1 (9,007,199,254,740,991).

Composite Number
180

180 is a composite number divisible by 2.

Canonical Prime Factorization
2^2 × 3^2 × 5
Product of prime powers: 2^2 × 3^2 × 5^1
Nearest Primes
Prev: 179
Next: 181
Immediate preceding and succeeding primes
Divisor Stats (τ and σ)
Count τ(n): 18
Sum σ(n): 546
Number of positive integer factors

All Positive Divisors (18 total)

123456910121518203036456090180

Prime Numbers & The Fundamental Theorem of Arithmetic

The Fundamental Theorem of Arithmetic

Every positive integer greater than 1 can be represented uniquely as a product of prime powers, up to the order of the factors.

For example, 180 = 2² × 3² × 5. Prime numbers are the fundamental multiplicative building blocks of all integers.

Deterministic Miller-Rabin Primality Test

Simple trial division testing up to √n becomes too slow for 16-digit integers.

The deterministic Miller-Rabin test checks modular square roots of 1 using Fermat's Little Theorem bases: [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37], guaranteeing 100% accuracy for all 64-bit integers.

Divisor Counting Formula τ(n)

If a number factors into p₁^a × p₂^b × p₃^c, the total number of positive divisors is:

τ(n) = (a + 1)(b + 1)(c + 1)

For 180 (2² × 3² × 5¹): (2+1)(2+1)(1+1) = 3 × 3 × 2 = 18 divisors.