# 53 (number)

 ← 52 53 54 →
Cardinal fifty-three
Ordinal 53rd
(fifty-third)
Factorization prime
Divisors 1, 53
Roman numeral LIII
Binary 1101012
Ternary 12223
Quaternary 3114
Quinary 2035
Senary 1256
Octal 658
Duodecimal 4512
Vigesimal 2D20
Base 36 1H36

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

## 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.[1][2]

53 written in hexadecimal is 35, that is, the same characters used in the decimal representation, but reversed. At least four multiples of 53 share this property: 371 = 17316, 5141 = 141516, 99481 =1849916, and 8520280 = 82025816.

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 other fields

Fifty-three is:

A fan-built Herbie

## References

1. ^ (sequence A045345 in OEIS)
2. ^ Puzzle 31.- The Average Prime number, APN(k) = S(Pk)/k from The Prime Puzzles & Problems Connection website