87 (number)

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 = 2² + 3² + 5² + 7²).
• 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).
• together with
  semiprimes; the first comprising 33, 34, 35
  .
• with an
  3
  -aliquot tree.
• 5! - 4! - 3! - 2! - 1! = 87
• the last two decimal digits of Graham's number.

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 are not as common as 87 on its own.^[5]
• 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
  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
  H0 scale is 1:87.^[6] Proto:87
  scale claims to offer precise proportions of wheels and tracks of real railroads.
• '87 and Cry
  ".
• The 87th United States Congress met from January 3, 1961, to January 3, 1963, during John F. Kennedy's time in office.
• Ed McBain's 87th Precinct: Lightning film starred Randy Quaid
  (1995).
• 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