53 (fifty-three) is the natural number following 52 and preceding 54.

In mathematics

Fifty-three is the 16th smallest prime number. The next is fifty-nine. Fifty-three is also a Sophie Germain prime, and the sum of five consecutive primes (5 + 7 + 11 + 13 + 17). It is an Eisenstein prime with no imaginary part and real part of the form $3n\; -\; 1$. Since 53 is equal to the arithmetic mean of its two neighboring primes, 47 and 59, it is a balanced prime.

53 is a strictly non-palindromic number.

53 written in hexadecimal is 35, that is, the same characters used in the decimal representation, but reversed. Three multiples of 53 share this property: 371 = 173₁₆, 5141 = 1415₁₆, 99481 = 18499₁₆.

But 53 can not be expressed as the sum of any integer and its base 10 digits, making 53 a self number.

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 object NGC 53, a magnitude 12.6 barred spiral galaxy in the constellation Tucana

• The Saros number of the solar eclipse series which began on -1295 August 26 and ended on 220 February 21. The duration of Saros series 53 was 1514.5 years, and it contained 85 solar eclipses.

• The Saros number of the lunar eclipse series which began on -993 June 5 and ended on 287 July 12. The duration of Saros series 53 was 1280.1 years, and it contained 72 lunar eclipses.

In other fields

Fifty-three is also:

• The code for international direct dial phone calls to Cuba.
• The racing number of Herbie, a Volkswagen Beetle with a mind of his own, first appearing in the 1968 movie The Love Bug.
• In the title of the 1912 movie North of Fifty Three, remade in 1917.
• The jersey number of Los Angeles Dodgers pitcher Don Drysdale.
• The jersey number of Philadelphia Phillies right fielder Bobby Abreu.
• The number of short poems in the book Rumi Birdsong by Jelaluddin Rumi.
• The year AD 53, 53 BC, and 1953.
• The name of a webcomic by Daniel Creamer. See Number 53 (webcomic)

53 (лік) | Cincuenta y tres | Kvindek tri | 53 (nombre) | 53 | 53 | Cinquantatré | 53 (skaičius) | 53 (getal) | 53 | Cinqüenta e três | 53 (число) | 53 (število) | 53 (tal) | 53 | 53