37 (thirty-seven) is the natural number following 36 and preceding 38.

In mathematics

• 37 is the 12th prime number, a permutable prime with 73 (which is the 21st prime number). 37 is the fifth lucky prime,^[1] the first irregular prime,^[2] the third unique prime^[3] and the third cuban prime of the form^[4]

${\displaystyle p={\frac {x^{3}-y^{3)){x-y))\qquad \left(x=y+1\right).}$

• 37 is the smallest prime that is not also a supersingular prime.^{[citation needed]}
• 37 is a centered hexagonal number^[5] and a star number.^[6]
• Every positive integer is the sum of at most 37 fifth powers (see Waring's problem).^[7]
• 37 appears in the Padovan sequence, preceded by the terms 16, 21, and 28 (it is the sum of the first two of these).^[8]
• Since the greatest prime factor of 37² + 1 = 1370 is 137, which is substantially more than 37 twice, 37 is a Størmer number.^[9]
• For a three-digit number that is divisible by 37, a rule of divisibility is that another divisible by 37 can be generated by transferring first digit onto the end of a number. For example: 37|148 ➜ 37|481 ➜ 37|814.^[10]

In science

• The atomic number of rubidium
• The normal human body temperature in degrees Celsius

Astronomy

• Messier object M37, a magnitude 6.0 open cluster in the constellation Auriga
• The New General Catalogue object NGC 37, a spiral galaxy in the constellation Phoenix
• Kepler-37b is the smallest known planet.
• NGC 2169 is known as the 37 Cluster, due to its resemblance of the numerals.

In sports

José María López used this number during his successful years in the World Touring Car Championship from 2014 until 2016. He still uses this number in Formula E since joining in 2016-17 season with DS Virgin Racing.

In other fields

House number in Baarle (in its Belgian part)

Thirty-seven is:

• The number of the French department Indre-et-Loire^[11]
• The number of slots in European roulette (numbered 0 to 36, the 00 is not used in European roulette as it is in American roulette)
• The number of Great Nats traditionally worshiped in Burma
• The RSA public exponent used by PuTTY
• +37 was the international dialing code of the German Democratic Republic (aka East Germany). Today the +37 prefix is shared by Lithuania (+370), Latvia (+371), Estonia (+372), Moldova (+373), Armenia (+374), Belarus (+375), Andorra (+376), Monaco (+377), San Marino (+378) and Vatican City (+379).
• The number of seconds of church-bell and thunderstorm recording before the opening tritone riff in the song "Black Sabbath" on the album Black Sabbath by the band Black Sabbath, which is considered to mark the birth of heavy metal music.
• Richard Nixon, 37th president of the United States.