39 (number)

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← 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	39 thirty-nine
Ordinal	39th thirty-ninth
Factorization	$3\cdot 13$
Divisors	1, 3, 13, 39
Roman numeral	XXXIX
Binary	100111
Hexadecimal	27

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

1 In mathematics
2 In science
- 2.1 Astronomy
3 In religion
4 In other fields
5 Historical years

[edit] In mathematics

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).

Thirty-nine is the sum of five consecutive primes (3 + 5 + 7 + 11 + 13) and the sum of the first three powers of 3 ( $31 + 3 2 + 3 3$ ). Given 39, the Mertens function returns 0.

39 is the smallest integer 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 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.

According to David Wells in The Penguin Dictionary of Curious and Interesting Numbers, 39 is the smallest mathematically uninteresting number. Doesn't that make it interesting?

[edit] In science

The atomic number of yttrium

[edit] 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
- solar eclipse series which began on -1718 May 26 and ended on -438 July 3. The duration of Saros series 39 was 1280.1 years, and it contained 72 solar eclipses.
- 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.

[edit] 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

[edit] In other fields

Thirty-nine is:

In the title of the John Buchan novel and subsequent films (one by Alfred Hitchcock), The Thirty-Nine Steps
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.
The eternal age of comedian Jack Benny, and many other people as they grow older
The traditional number of times citizens of Ancient Rome hit their slaves when beating them, referred to as "Forty save one"
Japanese Internet chat slang for "thank you" when written with numbers
"'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
"39" is a song by The Cure on their album "Bloodflowers"
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
World War II broke out in Europe on September 1, 1939
Pier 39 in San Francisco
The retired jersey number of former baseball great Roy Campanella
Uniform of former Pittsburgh Pirate Dave Parker
Uniform of football's Larry Csonka of Miami Dolphins; Hugh McElhenny of the San Francisco 49ers; and Steven Jackson of the St. Louis Rams
Super Bowl XXXIX, a Super Bowl in the 2004-2005 National Football League season between the New England Patriots and the Philadelphia Eagles in Jacksonville, Florida.

At age 39:

Apollo 11 commander Neil Armstrong became the 1st person to set foot on the moon
Charles Goodyear led the way to the effective use of rubber
Jimmy Connors reached the U.S. Open semifinals
Malcom X and Martin Luther King Jr. were assassinated
Amelia Earhardt went missing. She was declared dead 2 years later. 1937