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!
1619โ1621, 1667โ1669, 1697โ1699, 1721โ1723, 1787โ1789 ...
1663โ1667, 1693โ1697, 1783โ1787 ...
1613โ1619, 1621โ1627, 1657โ1663, 1741โ1747, 1747โ1753, 1753โ1759, 1777โ1783 ...
Primes of the form 2โฟ - 1 less than 1709
Primes that read the same forwards and backwards
Primes that remain prime when digits are rotated (below 1709)
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