51728 has 20 divisors (see below), whose sum is σ = 103788. Its totient is φ = 24960.

The previous prime is 51721. The next prime is 51749. The reversal of 51728 is 82715.

51728 is nontrivially palindromic in base 3.

It can be written as a sum of positive squares in 2 ways, for example, as 16384 + 35344 = 128^2 + 188^2 .

It is a Smith number, since the sum of its digits (23) coincides with the sum of the digits of its prime factors.

It is a plaindrome in base 14.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (51721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 818 + ... + 878.

2⁵¹⁷²⁸ is an apocalyptic number.

It is an amenable number.

51728 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (51894).

51728 is a wasteful number, since it uses less digits than its factorization.

51728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122 (or 116 counting only the distinct ones).

The product of its digits is 560, while the sum is 23.

The square root of 51728 is about 227.4379036133. The cubic root of 51728 is about 37.2599180833.

It can be divided in two parts, 517 and 28, that added together give a palindrome (545).

The spelling of 51728 in words is "fifty-one thousand, seven hundred twenty-eight".