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!
3917โ3919, 3929โ3931, 4001โ4003, 4019โ4021, 4049โ4051 ...
3907โ3911, 3919โ3923, 3943โ3947, 4003โ4007 ...
3911โ3917, 3923โ3929, 4007โ4013, 4013โ4019, 4021โ4027, 4051โ4057, 4073โ4079 ...
Primes of the form 2โฟ - 1 less than 3989
Primes that read the same forwards and backwards
Primes that remain prime when digits are rotated (below 3989)
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