Prime and Composite Numbers

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Numbers that can only be divided evenly by themselves and 1, and numbers that can be factored into smaller whole numbers.

What are Prime Numbers: A prime number is a positive integer greater than 1 that has no positive integer divisors other than 1 and itself.
How to Find Prime Numbers: There are various methods to identify prime numbers such as the Sieve of Eratosthenes or the divisibility test.
Composite Numbers: A composite number is a positive integer that has at least one positive divisor other than 1 and itself.
Difference Between Prime and Composite Numbers: The main difference is that prime numbers have only two divisors, whereas composite numbers have more than two.
Patterns in Prime Numbers: Prime numbers don't follow predictable patterns or sequences, but there are some patterns, such as the Prime Number Theorem.
Factors and Multiples: Factors and multiples are related to prime numbers and composite numbers. A factor is a positive integer that divides evenly into another integer, while a multiple is the result of multiplying a number by an integer.
Prime Factorization: Prime factorization is the process of breaking down a composite number into its prime factors. It is essential in cryptography and number theory.
Common Factors and Greatest Common Factor: Common factors are divisors that two or more numbers share. The greatest common factor (GCF) is the largest common factor that two or more numbers share.
Least Common Multiple: The least common multiple (LCM) is the smallest positive integer that is a multiple of two or more numbers.
Coprime Numbers: Coprime numbers are two or more numbers that have no common factors other than 1.
Goldbach's Conjecture: Goldbach's Conjecture states that every even number greater than 2 can be expressed as the sum of two primes.
Twin Primes: Twin primes are pairs of prime numbers that differ by two, such as 3 and 5, 5 and 7, or 11 and 13.
Mersenne Primes: Mersenne primes are prime numbers that can be expressed in the form of 2^n - 1, where n is a prime number.
Fermat's Little Theorem: Fermat's Little Theorem states that if p is a prime number and a is any positive integer not divisible by p, then a^(p-1) - 1 is divisible by p.
Euler's Totient Function: Euler's Totient Function is a mathematical function that gives the number of positive integers that are coprime to a given positive integer n.
Mersenne prime: A prime number of the form 2ⁿ − 1, where n is a positive integer.
Fermat prime: A prime number of the form 2²ⁿ + 1, where n is a positive integer.
Twin primes: Two prime numbers that differ by two.
Sophie Germain prime: A prime number p such that 2p + 1 is also prime.
Circular primes: A prime number whose digits, when rotated, generate a different prime number.
Cunningham chain: A sequence of prime numbers where each prime is of the form k×2ⁿ ± 1, where k and n are positive integers.
Abundant numbers: A number where the sum of its proper divisors is greater than the number itself.
Deficient numbers: A number where the sum of its proper divisors is less than the number itself.
Pronic numbers: A composite number that is the product of two consecutive integers.
Perfect numbers: A number where the sum of its proper divisors is equal to the number itself.
Compound numbers: A number that has more than two factors.
Hyperperfect numbers: A number where the sum of its proper divisors is one less than a power of two.
Quote: "A prime number (or a prime) is a natural number greater than 1 that is not a product of two smaller natural numbers."
Quote: "A natural number greater than 1 that is not prime is called a composite number."
Quote: "5 is prime because the only ways of writing it as a product, 1 × 5 or 5 × 1, involve 5 itself."
Quote: "4 is composite because it is a product (2 × 2) in which both numbers are smaller than 4."
Quote: "Every natural number greater than 1 is either a prime itself or can be factorized as a product of primes that is unique up to their order."
Quote: "The property of being prime is called primality."
Quote: "Trial division tests whether n is a multiple of any integer between 2 and √n."
Quote: "Faster algorithms include the Miller–Rabin primality test."
Quote: "As of December 2018, the largest known prime number is a Mersenne prime with 24,862,048 decimal digits."
Quote: "The prime number theorem... says that the probability of a randomly chosen large number being prime is inversely proportional to its number of digits, that is, to its logarithm."
Quote: "These include Goldbach's conjecture... and the twin prime conjecture."
Quote: "Primes are used in several routines in information technology, such as public-key cryptography, which relies on the difficulty of factoring large numbers into their prime factors."
Quote: "Such questions spurred the development of various branches of number theory, focusing on analytic or algebraic aspects of numbers."
Quote: "Objects that behave in a generalized way like prime numbers include prime elements and prime ideals."
Quote: "As demonstrated by Euclid around 300 BC, there are infinitely many primes."
Quote: "No known simple formula separates prime numbers from composite numbers."
Quote: "The distribution of primes within the natural numbers in the large can be statistically modeled."
Quote: "The AKS primality test always produces the correct answer in polynomial time but is too slow to be practical."
Quote: "Particularly fast methods are available for numbers of special forms, such as Mersenne numbers."
Quote: "For example, 5 is prime..."