# 87 (number)

From HandWiki

__: Natural number__

**Short description**
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---|---|---|---|---|

Cardinal | eighty-seven | |||

Ordinal | 87th (eighty-seventh) | |||

Factorization | 3 × 29 | |||

Divisors | 1, 3, 29, 87 | |||

Greek numeral | ΠΖ´ | |||

Roman numeral | LXXXVII | |||

Binary | 1010111_{2} | |||

Ternary | 10020_{3} | |||

Quaternary | 1113_{4} | |||

Quinary | 322_{5} | |||

Senary | 223_{6} | |||

Octal | 127_{8} | |||

Duodecimal | 73_{12} | |||

Hexadecimal | 57_{16} | |||

Vigesimal | 47_{20} | |||

Base 36 | 2F_{36} |

**87** (**eighty-seven**) is the natural number following 86 and preceding 88.

## In mathematics

**87** is:

- the sum of the squares of the first four primes (87 = 2
^{2}+ 3^{2}+ 5^{2}+ 7^{2}). - the sum of the sums of the divisors of the first 10 positive integers.
^{[1]} - the thirtieth semiprime,
^{[2]}and the twenty-sixth distinct semiprime^{[3]}and the eighth of the form (3.q). - 5! - 4! - 3! - 2! - 1! = 87

## In sports

- Cricket in Australia holds 87 as a superstitiously unlucky score and is referred to as "the devil's number." This originates from the fact that 87 is 13 runs short of a century. 187, 287 and so on are also considered unlucky but is not as common as 87 on its own.
^{[4]} - In the National Hockey League, Wayne Gretzky scored a league-high 87 goals with the Edmonton Oilers in the 1983–84 NHL season.

## In other fields

**Eighty-seven** is also:

- The atomic number of francium.
- An answer to a popular puzzle question states 16, 06, 68, 88, xx, 98. The answer is 87 when looked upside down.
- The number of years between the signing of the U.S. Declaration of Independence and the Battle of Gettysburg, immortalized in Abraham Lincoln's Gettysburg Address with the phrase "
*Four Score*and Seven Years ago..." - The model number of Junkers Ju 87.
- The number of the French department Haute-Vienne.
- The code for international direct dial phone calls to Inmarsat and other services.
- The 87 photographic filter blocks visible light allowing only infrared light to pass.
- The ISBN Group Identifier for books published in Denmark.
- The opus number of the 24 Preludes and Fugues of Dmitri Shostakovich.
- In model railroading, the ratio of the popular H0 scale is 1:87.
^{[5]}Proto:87 scale claims to offer precise proportions of wheels and tracks of real railroads. - David Bowie CD (1987)
*Never Let Me Down*includes the song, "'87 and Cry". - The 87th United States Congress met from January 3, 1961 - January 3, 1963, during John F. Kennedy's time in office.
- Ed McBain's
*87th Precinct: Lightning*film starred Randy Quaid (1995). - 87 punch includes one bottle of Bacardi rum (eight years aged) and 7-up (two-liter bottle).
- Wenger Swiss Army Knife version XXL, listed in the
*Guinness Book of World Records*as the world's most multi-functional penknife with 87 tools. *Sonnet 87*by William Shakespeare.- Vault 87 is a main location in the game
*Fallout 3*. - M87* is the first black hole ever photographed.
- Aragorn's age in
*The Lord of the Rings*. - "The Bite of '87" in the
*Five Nights at Freddy's*series.

## See also

- List of highways numbered 87

## References

- ↑ Sloane, N. J. A., ed. "Sequence A024916 (sum_{k=1..n} sigma(k) where sigma(n) = sum of divisors of n)". OEIS Foundation. https://oeis.org/A024916.
- ↑ "A001358 - OEIS". https://oeis.org/A001358.
- ↑ "A006881 - OEIS". https://oeis.org/A006881.
- ↑ Ferris, Sam (2014-11-02). "The real story behind Australia's unlucky number 87" (in en). https://www.cricket.com.au/news/the-story-behind-unlucky-number-87/2014-11-02.
- ↑ "Guide to model railroading scales and gauges".
*Model Railroader*. 2 November 2011. http://mrr.trains.com/how-to/get-started/2011/11/your-guide-to-scales-and-gauges.

Original source: https://en.wikipedia.org/wiki/87 (number).
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