39 (number)

← 38 40 → 39
← 30 31 32 33 34 35 36 37 38 39 → List of numbers — Integers 0 10 20 30 40 50 60 70 80 90 →
Cardinal	thirty-nine
Ordinal	39th (thirty-ninth)
Factorization	$3 \cdot 13$
Divisors	1, 3, 13, 39
Roman numeral	XXXIX
Binary	1001112
Octal	478
Duodecimal	3312
Hexadecimal	2716

39 (thirty-nine) is the natural number following 38 and preceding 40.

In mathematics

The F26A graph has 39 edges, all equivalent.

Thirty-nine is the sum of five consecutive primes (3 + 5 + 7 + 11 + 13) and the sum of the first three powers of 3 (3¹ + 3² + 3³). Given 39, the Mertens function returns 0.

39 is the smallest natural number which has three partitions into three parts which all give the same product when multiplied: {25, 8, 6}, {24, 10, 5}, {20, 15, 4}.

39 is the 12th distinct semiprime and the 4th in the {3.q} family. It is the last member of the third distinct biprime pair (38,39).

39 has an aliquot sum of 17 which is itself a prime. 39 is the 4th member of the 17-aliquot tree

The thirteenth Perrin number is 39, which comes after 17, 22, 29 (it is the sum of the first two mentioned).

Since the greatest prime factor of 39² + 1 = 1522 is 761, which is obviously more than 39 twice, 39 is a Størmer number.

The F26A graph is a symmetric graph with 39 edges.

In science

• The atomic number of yttrium

Astronomy

• Messier object Open Cluster M39, a magnitude 5.5 open cluster in the constellation Cygnus
• The New General Catalogue object NGC 39, a spiral galaxy in the constellation Andromeda
• The Saros number of the
  • lunar eclipse series which began on -1380 March 26 and ended on -82 May 14. The duration of Saros series 39 was 1298.1 years, and it contained 73 lunar eclipses.

In religion

• The number of the 39 categories of activity prohibited on Shabbat according to Halakha
• The number of mentions of work or labor in the Torah
• The actual number of lashes given by the Sanhedrin to a person meted the punishment of 40 lashes
• The number of books in the Old Testament according to Protestant canon
• The number of statements on Anglican Church doctrine, Thirty-Nine Articles

In other fields

Arts and entertainment

• In the title of the John Buchan novel and subsequent films (one by Alfred Hitchcock), The Thirty-Nine Steps
• The age American comedian Jack Benny claimed to be for more than 40 years
• "39" is a song by The Cure on their album "Bloodflowers"
• "'39" is a track on Queen's album A Night At the Opera. If the tracks on Queen's original studio albums are numbered in sequential order starting with their first, "'39" does in fact fall in the thirty-ninth position
• The retired jersey number of former baseball player Roy Campanella
• The book series "The 39 Clues" revolves around 39 clues hidden around the world.
• Glorious 39 is a 2009 drama film set at the beginning of World War II
• In the CBS reality show Survivor, contestants compete for 39 days.

History

• The number of signers to the United States Constitution, out of 55 members of the Philadelphia Convention delegates
• The traditional number of times citizens of Ancient Rome hit their slaves when beating them, referred to as "Forty save one"
• The duration, in nanoseconds, of the nuclear reaction in the largest nuclear explosion ever performed (Tsar bomb)
• The number of Scud missiles which Iraq fired at Israel during the Gulf War in 1991

Other

• The code for international direct-dialed phone calls to Italy
• I-39 is the designation for a US interstate highway from Normal, Illinois to Wausau, Wisconsin. I-39 is the 39th shortest of the primary "two digit" Interstates.
• Japanese Internet chat slang for "thank you" when written with numbers (3=san 9=kyu)
• Pier 39 in San Francisco
• The number of the French department Jura
• A cursed number according to popular superstition in Afghanistan.

Historical years

39 A.D., 39 B.C., 1939, 2039, etc.