Cheryl

Cheryl is a female given name common in English speaking countries.

The name appeared in the early 20th century and was most popular during the early Cold War period. In America it was most popular from the 1940s to early 1980s and in the UK from the 1950s to early 1990s.

There are several prevailing theories about its etymology. The most common is that it has Italo-Celtic roots and is an Anglicised version of either the French name Cherie (from Latin Cara, being "beloved"; see also Carissa (name)) or the Welsh name Carys (a cognate of "Cara"), modelled on names such as Meryl and Beryl that were popular during the early decades of the 20th century.

A less popular theory is that the name is Germanic in origin and is a feminine version of the Germanic male name Charles, which means "free man". An Anglo-Saxon (male) variant of Charles is Ceorl. Feminine variations of Charles include Charlotte, Carly, Carla and Caroline.

Notable people

Prime number

A prime number (or a prime) is a natural number greater than 1 that has no positive divisors other than 1 and itself. A natural number greater than 1 that is not a prime number is called a composite number. For example, 5 is prime because 1 and 5 are its only positive integer factors, whereas 6 is composite because it has the divisors 2 and 3 in addition to 1 and 6. The fundamental theorem of arithmetic establishes the central role of primes in number theory: any integer greater than 1 can be expressed as a product of primes that is unique up to ordering. The uniqueness in this theorem requires excluding 1 as a prime because one can include arbitrarily many instances of 1 in any factorization, e.g., 3, 1 · 3, 1 · 1 · 3, etc. are all valid factorizations of 3.

The property of being prime (or not) is called primality. A simple but slow method of verifying the primality of a given number n is known as trial division. It consists of testing whether n is a multiple of any integer between 2 and . Algorithms much more efficient than trial division have been devised to test the primality of large numbers. These include the Miller–Rabin primality test, which is fast but has a small probability of error, and the AKS primality test, which always produces the correct answer in polynomial time but is too slow to be practical. Particularly fast methods are available for numbers of special forms, such as Mersenne numbers. As of January 2016, the largest known prime number has 22,338,618 decimal digits.