Discover if your number is Prime or Composite โ fast and easy!
โ Yes! It's a Prime Number
Prime numbers are only divisible by 1 and itself.
Explore comprehensive data about prime numbers and their fascinating properties.
Click any prime to analyze it!
3โ5, 5โ7, 11โ13, 17โ19, 29โ31, 41โ43, 59โ61, 71โ73 ...
7โ11, 13โ17, 19โ23, 37โ41, 43โ47, 67โ71, 79โ83 ...
23โ29, 31โ37, 47โ53, 53โ59, 61โ67, 73โ79, 83โ89 ...
Primes of the form 2โฟ - 1 less than 7
Primes that read the same forwards and backwards
Primes that remain prime when digits are rotated (below 7)
Prime numbers are the building blocks of mathematics, encryption, and more. Explore what makes them fascinating.
A prime number is a natural number greater than 1 that has no positive divisors other than 1
and itself.
Prime numbers cannot be formed by multiplying two smaller natural numbers. The first few are:
2, 3, 5, 7, 11, 13, 17, 19, 23...
ฯ(n) โ n/ln(n) - The density of primes decreases logarithmically
ฮถ(s) = 0 only at s = -2,-4,-6... and Re(s) = 1/2
For n > 1, there's always a prime between n and 2n
Test divisibility up to โn - Simple but slow O(โn)
Probabilistic test - Fast O(k logยณ n) with k rounds