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Arabic numerals
Arabic numerals are the ten symbols most commonly used to write numbers: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. The term often implies a decimal number, in particular when contrasted with Roman numerals, however the symbols are also used for writing numbers in other systems such as octal, and for writing identifiers such as computer symbols, trademarks, or license plates. They are also called Western Arabic numerals, Ghubār numerals, Hindu-Arabic numerals, Western digits, Latin digits, or European digits.
17 (number)
17 (seventeen) is the natural number following 16 and preceding 18. It is a prime number. Seventeen is the sum of the first four prime numbers. Seventeen is the seventh prime number, which makes it the fourth super-prime, as seven is itself prime. It forms a twin prime with 19, a cousin prime with 13, and a sexy prime with both 11 and 23. Seventeen is the only prime number which is the sum of four consecutive primes (2, 3, 5, and 7), as any other four consecutive primes that are added always generate an even number divisible by two.
Gematria
Gematria (gəˈmeɪtriə; גמטריא or gimatria גימטריה, plural גמטראות or גימטריאות, gimatriot) is the practice of assigning a numerical value to a name, word or phrase by reading it as a number, or sometimes by using an alphanumerical cipher. The letters of the alphabets involved have standard numerical values, but a word can yield several values if a cipher is used. According to Aristotle (384–322 BCE), isopsephy, based on the Milesian numbering of the Greek alphabet developed in the Greek city of Miletus, was part of the Pythagorean tradition, which originated in the 6th century BCE.
24 (number)
24 (twenty-four) is the natural number following 23 and preceding 25. 24 is an even composite number, with 2 and 3 as its distinct prime factors. It is the first number of the form 2^qq, where q is an odd prime. It is the smallest number with at least eight positive divisors: 1, 2, 3, 4, 6, 8, 12, and 24; thus, it is a highly composite number, having more divisors than any smaller number. Furthermore, it is an abundant number, since the sum of its proper divisors (36) is greater than itself, as well as a superabundant number.
Babylonian cuneiform numerals
Assyro-Chaldean Babylonian cuneiform numerals were written in cuneiform, using a wedge-tipped reed stylus to make a mark on a soft clay tablet which would be exposed in the sun to harden to create a permanent record. The Babylonians, who were famous for their astronomical observations, as well as their calculations (aided by their invention of the abacus), used a sexagesimal (base-60) positional numeral system inherited from either the Sumerian or the Akkadian civilizations.
18 (number)
18 (eighteen) is the natural number following 17 and preceding 19. Eighteen is a composite number, its divisors being 1, 2, 3, 6 and 9. Three of these divisors (3, 6 and 9) add up to 18, hence 18 is a semiperfect number. Eighteen is the first inverted square-prime of the form p·q2. In base ten, it is a Harshad number. It is an abundant number, as the sum of its proper divisors is greater than itself (1+2+3+6+9 = 21). It is known to be a solitary number, despite not being coprime to this sum.
Chinese numerology
Some numbers are believed by some to be auspicious or lucky (吉利, ) or inauspicious or unlucky (不吉, ) based on the Chinese word that the number sounds similar to. The numbers 2, 3, 6, and 8 are generally considered to be lucky, while 4 is considered unlucky. These traditions are not unique to Chinese culture, with other countries with a history of Han characters also having similar beliefs stemming from these concepts. The number 0 (零, ) is the beginning of all things and is generally considered a good number, because it sounds like 良 (pinyin: liáng), which means 'good'.
64 (number)
64 (sixty-four) is the natural number following 63 and preceding 65. Sixty-four is the square of 8, the cube of 4, and the sixth-power of 2. It is the smallest number with exactly seven divisors. 64 is the first non-unitary sixth-power prime of the form p6 where p is a prime number. The aliquot sum of a 2-power (2n) is always one less than the 2-power itself therefore the aliquot sum of 64 is 63, within an aliquot sequence of two composite members ( 64,63,41,1,0) to the prime 41 in the 41-aliquot tree.
Pierpont prime
In number theory, a Pierpont prime is a prime number of the form for some nonnegative integers u and v. That is, they are the prime numbers p for which p − 1 is 3-smooth. They are named after the mathematician James Pierpont, who used them to characterize the regular polygons that can be constructed using conic sections. The same characterization applies to polygons that can be constructed using ruler, compass, and angle trisector, or using paper folding. Except for 2 and the Fermat primes, every Pierpont prime must be 1 modulo 6.
Double Mersenne number
In mathematics, a double Mersenne number is a Mersenne number of the form where p is prime. The first four terms of the sequence of double Mersenne numbers are : A double Mersenne number that is prime is called a double Mersenne prime. Since a Mersenne number Mp can be prime only if p is prime, (see Mersenne prime for a proof), a double Mersenne number can be prime only if Mp is itself a Mersenne prime. For the first values of p for which Mp is prime, is known to be prime for p = 2, 3, 5, 7 while explicit factors of have been found for p = 13, 17, 19, and 31.