Prime numbers are positive integers which have only
two divisors: one and itself. For example, 23 is a prime number because its only
divisors are 1 and 23. Based on this definition, one is not a prime number
because it has only one divisor. Some of the small prime numbers include:
2, 3, 5, 7, 11, 13, 17, 19,
23, 29, 31, 37, 41, .....
There are an infinite number of prime numbers.
Neither is there a largest prime number.
Any natural number which is a multiple of
a smaller integer other than one is not a prime number. These numbers are
called composite numbers. Because all even numbers greater than two are
multiples of two, all even numbers except two are not prime numbers. In
other words, two is the only even prime number.
Prime numbers have captured the hearts of
many mathematicians for centuries. Euclid proved that there is
no largest prime number. During 18th century, mathematician
Christian Goldbach (1690-1764) wrote to
Leonhard Euler that he believed it could be
shown that every even integer greater than 2 is the sum of 2 primes.
For example, 30 = 23+7 and 36 = 13+23. Until now, this
conjecture has neither been proved or disproved.
In the present age of information
technology where we find vital information being transmitted via the internet,
prime numbers found its usefulness in information security, message encoding,
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