53 (fifty-three) is the

natural number In mathematics, the natural numbers are the numbers 0, 1, 2, 3, and so on, possibly excluding 0. Some start counting with 0, defining the natural numbers as the non-negative integers , while others start with 1, defining them as the positive in ...

following 52 and preceding 54. It is the 16th

prime number A prime number (or a prime) is a natural number greater than 1 that is not a Product (mathematics), product of two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number. For example, 5 is prime ...

In mathematics

Fifty-three is the 16th

. It is the second balanced prime, and fifth isolated prime. 53 is a sexy prime with 47 and 59. It is the eighth Sophie Germain prime, and the ninth Eisenstein prime. The sum of the first 53 primes is 5830, which is divisible by 53, a property shared by only a few other numbers. 53 cannot be expressed as the sum of any integer and its decimal digits, making 53 the ninth self number in decimal. 53 is the smallest prime number that does not divide the order of any sporadic group, inclusive of the six pariahs; it is also the first prime number that is not a member of Bhargava's prime-universality criterion theorem (followed by the next prime number 59), an integer-matrix quadratic form that represents all prime numbers when it represents the sequence of seventeen integers . In

hexadecimal Hexadecimal (also known as base-16 or simply hex) is a Numeral system#Positional systems in detail, positional numeral system that represents numbers using a radix (base) of sixteen. Unlike the decimal system representing numbers using ten symbo ...

, 53 is 35, that is, the same characters used in the decimal representation, but reversed. Four additional multiples of 53 share this property: 371 = , 5141 = , 99,481 = , and 8,520,280 = 0. Aside from the trivial single digit numbers, these are the only numbers that share this property.

References

Integers {{Num-stub