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 = 17316, 5141 = 141516, 99481 = 1849916, and 8520280 = 082025816. 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.