๐Ÿ”ข Prime Number Checker

Discover if your number is Prime or Composite โ€“ fast and easy!

Number: 7

โœ… Yes! It's a Prime Number

Prime numbers are only divisible by 1 and itself.

๐Ÿง  Did You Know?

  • 2 is the smallest and only even prime number.
  • Prime numbers play a key role in cryptography.
  • Every number is either prime, composite, or 1.
  • There are infinitely many prime numbers.
  • Mathematicians use prime numbers in advanced theories.

๐ŸŽฏ Prime Number Database

Explore comprehensive data about prime numbers and their fascinating properties.

๐Ÿ“ˆ Prime Gaps Analysis Around 7

Twin Primes (Gap = 2)

3โ€“5, 5โ€“7, 11โ€“13, 17โ€“19, 29โ€“31, 41โ€“43, 59โ€“61, 71โ€“73 ...

Cousin Primes (Gap = 4)

7โ€“11, 13โ€“17, 19โ€“23, 37โ€“41, 43โ€“47, 67โ€“71, 79โ€“83 ...

Gap-6 Primes

23โ€“29, 31โ€“37, 47โ€“53, 53โ€“59, 61โ€“67, 73โ€“79, 83โ€“89 ...

๐ŸŒŸ Mersenne Primes

Primes of the form 2โฟ - 1 less than 7

M2 = 3 (n=2)
M3 = 7 (n=3)

๐ŸŽญ Palindromic Primes

Primes that read the same forwards and backwards

2
3
5
7
11
101
131
151
181
191
313
353

๐Ÿ”„ Circular Primes

Primes that remain prime when digits are rotated (below 7)

2 (single digit)
3 (single digit)
5 (single digit)
7 (single digit)

๐Ÿ”ข Understanding Prime Numbers

Prime numbers are the building blocks of mathematics, encryption, and more. Explore what makes them fascinating.

What is a Prime Number?

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...

๐ŸŒ Real-World Uses

  • ๐Ÿ” RSA Encryption: Internet security
  • ๐Ÿ“ฑ Blockchain: Bitcoin mining
  • ๐ŸŽฒ Random Numbers: Gaming algorithms
  • ๐Ÿ’ป Hash Tables: Database optimization
  • ๐Ÿ›ก๏ธ Digital Signatures: Authentication
  • ๐Ÿ“ก Error Detection: Data transmission

๐Ÿงฎ Math Properties

  • 2 is the only even prime
  • All primes >3 are 6kยฑ1
  • Infinite quantity (Euclid's proof)
  • Fundamental Theorem of Arithmetic
  • Prime Number Theorem (density)
  • Goldbach's Conjecture

๐Ÿ“š Historical Facts

  • ๐Ÿ›๏ธ Known since ancient Greeks
  • ๐Ÿ“œ Sieve of Eratosthenes (276 BC)
  • ๐Ÿง  Fermat's Little Theorem (1640)
  • ๐ŸŽฏ Euler's work on primes (1700s)
  • ๐Ÿ† Riemann Hypothesis (1859)
  • ๐Ÿ’ฐ $1M Clay Prize problems

๐Ÿ† Modern Records

  • ๐Ÿฅ‡ Largest: 2โธยฒ,โตโธโน,โนยณยณ - 1
  • ๐Ÿ“ 24,862,048 digits long
  • ๐Ÿ–ฅ๏ธ Found by GIMPS project
  • โšก Distributed computing
  • ๐ŸŽ–๏ธ $150,000 prize awarded
  • ๐Ÿ” Search continues daily

๐ŸŽ“ Advanced Concepts

Prime Number Theorem

ฯ€(n) โ‰ˆ n/ln(n) - The density of primes decreases logarithmically

Riemann Hypothesis

ฮถ(s) = 0 only at s = -2,-4,-6... and Re(s) = 1/2

Bertrand's Postulate

For n > 1, there's always a prime between n and 2n

๐Ÿ”ฌ Testing Algorithms

Trial Division

Test divisibility up to โˆšn - Simple but slow O(โˆšn)

Miller-Rabin

Probabilistic test - Fast O(k logยณ n) with k rounds