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!
71โ73, 101โ103, 107โ109, 137โ139, 149โ151, 179โ181 ...
67โ71, 79โ83, 97โ101, 103โ107, 109โ113, 127โ131, 163โ167 ...
73โ79, 83โ89, 131โ137, 151โ157, 157โ163, 167โ173, 173โ179 ...
Primes of the form 2โฟ - 1 less than 127
Primes that read the same forwards and backwards
Primes that remain prime when digits are rotated (below 127)
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