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!
4001โ4003, 4019โ4021, 4049โ4051, 4091โ4093, 4127โ4129 ...
4003โ4007, 4129โ4133, 4153โ4157 ...
4007โ4013, 4013โ4019, 4021โ4027, 4051โ4057, 4073โ4079, 4093โ4099, 4133โ4139 ...
Primes of the form 2โฟ - 1 less than 4057
Primes that read the same forwards and backwards
Primes that remain prime when digits are rotated (below 4057)
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