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!
21191โ21193, 21317โ21319, 21377โ21379 ...
21187โ21191, 21313โ21317, 21319โ21323, 21379โ21383, 21397โ21401 ...
21163โ21169, 21221โ21227, 21277โ21283, 21341โ21347, 21391โ21397 ...
Primes of the form 2โฟ - 1 less than 21283
Primes that read the same forwards and backwards
Primes that remain prime when digits are rotated (below 21283)
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