87 (number)

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

← 86 88 → 87
← 80 81 82 83 84 85 86 87 88 89 → List of numbers — Integers 0 10 20 30 40 50 60 70 80 90 →
Cardinal	eighty-seven
Ordinal	87th (eighty-seventh)
Numeral system	87
Factorization	$3 \cdot 29$
Divisors	1, 3, 29, 87
Roman numeral	LXXXVII
Binary	10101112
Octal	1278
Duodecimal	7312
Hexadecimal	5716

In mathematics

Eighty-seven is the twenty-sixth distinct semiprime and the eighth of the form (3.q). The aliquot sum of 87 is 33 within the aliquot sequence (87,33,15,9,4,3,1,0) 86 being the eighteenth composite number in the 3-aliquot tree.

Eighty-seven is the sum of the squares of the first four primes. It is also the sum of the sum of divisors of the first ten integers.

In sports

• In cricket in Australia, 87 is considered an unlucky score (the devil's number) thought to originate from the fact that 87 is 13 runs short of a century, equivalent a Nelson's, Double-Nelson's etc. (111, 222 etc.) in English cricket.
• 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 year AD 87, 87 BC, or 1987
• The atomic number of francium
• 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 "fourscore and seven years ago..."
• The model number of Junkers Ju 87
• The number of the French department Haute-Vienne
• The designation of Interstate 87, a freeway in New York; the European route E87 from Tulcea to Antalya
• 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. 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 1 bottle of Bacardi Rum (8 years aged) and 7-up (2 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
• The U 87 is a popular microphone used for recording