53 (number)

In mathematics

• Fifty-three is the 16th prime number. It is also an Eisenstein prime, and a Sophie Germain prime.
• The sum of the first 53 primes is 5830, which is divisible by 53, a property shared by few other numbers.
• 53 written in hexadecimal is 35, that is, the same characters used in the decimal representation, but reversed. Four additional multiples of 53 share this property: 371 =, 5141 =, 99481 =, and 8520280 = 0. Apart from the trivial case of single-digit decimals, no other number has this property.
• 53 cannot be expressed as the sum of any integer and its base-10 digits, making 53 a self number.
• 53 is the smallest prime number that does not divide the order of any sporadic group.

  In science

• The atomic number of iodine

  Astronomy

• Messier object M53, a magnitude 8.5 globular cluster in the constellation Coma Berenices
• The New General Catalogue NGC 53, a magnitude 12.6 barred spiral galaxy in the constellation Tucana

  In other fields

• The racing number of Herbie, a fictional Volkswagen Beetle with a mind of his own, first appearing in the 1968 film The Love Bug
• The code for international direct dial phone calls to Cuba
• "53 Days" is a northeastern USA rock band
• "53 Days" a novel by Georges Perec
• In How the Grinch Stole Christmas!, and its animated TV special the Grinch says he's put up with the Whos' Christmas cheer for 53 years.
• Fictional 53rd Precinct in the Bronx was found in the TV comedy "Car 54, Where Are You?"
• "53rd & 3rd" a song by the Ramones
• The number of Hail Mary beads on a standard, five decade Catholic Rosary.
• The number of bytes in an Asynchronous Transfer Mode packet.
• UDP and TCP port number for the Domain Name System protocol.
• 53-TET is a musical temperament that has a fifth that is closer to pure than our current system.
• 53 More Things To Do In Zero Gravity is a book mentioned in The Hitchhiker's Guide to the Galaxy

  Sports

• The maximum number of players on a National Football League roster
• Most points by a rookie in an NBA playoff game, by Philadelphia's Wilt Chamberlain, 1960
• Most field goals, by Michael Jordan, 1992