Content deleted Content added
No edit summary |
m revert sock |
||
(427 intermediate revisions by more than 100 users not shown) | |||
Line 1:
{{Infobox number
[[Link title]]'''89''' ('''eighty-nine''') is the [[natural number]] following [[88 (number)|88]] and preceding [[90 (number)|90]].▼
| number = 89
| factorization = [[prime number|prime]]
| prime = 24th
| divisor = 1, 89
}}
▲
== In mathematics ==
'''89''' is:
* the 24th [[prime number]], following [[83 (number)|83]] and preceding [[97 (number)|97]].
* a [[Chen prime]].<ref>{{Cite web|url=https://oeis.org/A109611|title=Sloane's A109611 : Chen primes|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-05-29}}</ref>
* a [[Pythagorean prime]].<ref>{{Cite web|url=https://oeis.org/A002144|title=Sloane's A002144 : Pythagorean primes|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-05-29}}</ref>
* the smallest [[Sophie Germain prime]] to start a [[Cunningham chain]] of the first kind of six terms, {89, 179, 359, 719, 1439, 2879}.
* an [[Eisenstein prime]] with no imaginary part and real part of the form {{nowrap|3''n'' − 1}}.
* The 11th [[Fibonacci number]] and thus a [[Fibonacci prime]] as well.<ref>{{Cite web|url=https://oeis.org/A005478|title=Sloane's A005478 : Prime Fibonacci numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-05-29}}</ref> The first few digits of its reciprocal coincide with the Fibonacci sequence due to the identity
''M''<sub>89</sub> is the 10th [[Mersenne prime]].
▲<math>\frac{1}{89}=\sum_{n=1}^\infty{F(n)\times 10^{-(n+1)}}=0.011235955...</math>
Although 89 is not a [[Lychrel number]] in base 10, it is unusual that it takes 24 iterations of the reverse and add process to reach a [[palindrome]]. Among the known non-Lychrel numbers in the first 10000 integers, no other number requires that many or more iterations. The palindrome reached is also unusually large: 8813200023188.<ref>Weisstein, Eric W. "196-Algorithm." From MathWorld, a Wolfram Web Resource. [http://mathworld.wolfram.com/196-Algorithm.html http://mathworld.wolfram.com/196-Algorithm.html]</ref>▼
▲89 is also a [[Markov number]], appearing in solutions to the Markov Diophantine equation with other odd-indexed Fibonacci numbers.
There are exactly 1000 prime numbers between 1 and 89<sup>2</sup>=7921.<ref>{{Cite web |title=Prime Curios! 89 |url=https://primes.utm.edu/curios/page.php/89.html |access-date=2022-12-19 |website=primes.utm.edu}}</ref>
== In sports ==
▲Although 89 is not a [[Lychrel number]] in base 10, it is unusual that it takes 24 iterations of the reverse and add process to reach a palindrome. Among the known non-Lychrel numbers in the first 10000 integers, no other number requires that many or more iterations.
* The [[Oklahoma Redhawks]], an American [[minor league baseball]] team, were formerly known as the Oklahoma 89ers (1962–1997). The number alludes to the [[Land Run of 1889]], when the [[Unassigned Lands]] of Oklahoma were opened to [[White American|white]] settlement. The team's home of [[Oklahoma City]] was founded during this event.
* In [[List of rugby union terms|Rugby]], an "89" or eight-nine move is a phase following a scrum, in which the number 8 catches the ball and transfers it to number 9 (scrum half).
== In other fields ==
[[Image:
'''Eighty-nine''' is also:
* ''[[Information Is Beautiful]]'' cites [[Tiananmen Square protests of 1989|eighty-nine]] as one of the words censored on the [[Internet in China|Chinese internet]].<ref>{{cite web |url=http://www.informationisbeautiful.net/2010/what-does-china-censor-online/ |title=What Does China Censor Online? |website=www.informationisbeautiful.net |access-date=28 May 2015}}</ref>
==See also==
*[[Hellin's law]]
==References==
<references/>
{{Integers|zero}}
[[Category:Integers]]
|