18 (number)

18 (eighteen) is the natural number following 17 and preceding 19.

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Eighteen is a composite number, its proper divisors being 1, 2, 3, 6 and 9. It is a heptagonal number, and as the sum of the first three pentagonal numbers, it is a pentagonal pyramidal number. It is a Harshad number.

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18 (number): In mathematics ►

Natural number: Natural number can mean either a positive integer (, , , , ...) or a non-negative integer (, , , , , ...)....

Composite number: A composite number is a positive integer which has a positive divisor other than one or itself. By definition, every integer greater than one is either a prime number or a composite number. The numbers zero and one are considered to be neither prime nor composite. The integer 14 is a composite numbe...

Divisor: :For divisors in algebraic geometry, see divisor (algebraic geometry)....

18 (number) related Images and Photos (experimental)

Number 8 1949	Number 36	Number 23	Number 25
Number 23 (BD)	Number 18 1950	ABBA: Number Ones CD	ABBA: Number Ones CD
Number 23, The (DVD) (WS) (Rated/Unrated)	Summertime: Number 9A 1948	Tree Number Two	Gangster Number 1

~ Table of Content ~

►	Introduction
►	In mathematics
►	In science
►	In human affairs: Age 18
►	In Judaism
►	In other fields

►	FR: 18 (nombre)

~ Related Subjects ~

Integer (2) - Divisor (2) - 2 (2) - Positive (2) - Pentagonal pyramidal number (1) - Non-negative (1) - Harshad number (1) - 14 (1) - 7 (1) - Zero (1) - One (1) - Prime number (1) - Composite number (1) - 1 (1) - 19 (1) -

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