← 17 18 19 →
Cardinaleighteen
Ordinal18th
(eighteenth)
Numeral systemoctodecimal
Factorization2 × 32
Divisors1, 2, 3, 6, 9, 18
Greek numeralΙΗ´
Roman numeralXVIII
Binary100102
Ternary2003
Octal228
Duodecimal1612
Hexadecimal1216

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

In mathematics

In science

Chemistry

In religion and literature

As lucky or unlucky number

Age 18

See also: Age of majority, Voting age, Drinking age, Smoking age, Marriageable age, and Age of consent

In most countries, 18 is the age of majority, in which a minor becomes a legal adult. It is also the voting age, marriageable age, drinking age and smoking age in most countries, though sometimes these ages are different than the age of majority. Many websites restrict adult content to visitors who claim to be aged over 18.

In sports

See also

Notes

  1. ^ "Sloane's A005835 : Pseudoperfect (or semiperfect) numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-31.
  2. ^ Sloane, N. J. A. (ed.). "Sequence A000957". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-06-01.
  3. ^ Benjaminson, Chani. "What is the reason for the custom to give money gifts in multiples of 18 -- 18, 36, 54, etc.?". Chabad.org. Archived from the original on 2007-12-27. Retrieved January 19, 2022.
  4. ^ N James. The Early Composition History of Catch-22. In Biographies of Books: The Compositional Histories of Notable American Writings, J Barbour, T Quirk (edi.) pp. 262-90. Columbia: University of Missouri Press, 1996
  5. ^ 言必有「中」:「十八」「實發」 人見人愛. 文匯報. Accessed 2015-01-12. Archived 2015-01-15.
  6. ^ "Chai, Its Meaning and Significance | Shiva, Jewish Mourning". www.shiva.com. Retrieved 2020-11-18.
  7. ^ "STATUTORY RAPE: A GUIDE TO STATE LAWS AND REPORTING REQUIREMENTS. SEXUAL INTERCOURSE WITH MINORS". aspe.hhs.gov.
  8. ^ "Minimum Age". Giffords.