721928 has 32 divisors (see below), whose sum is σ = 1451520. Its totient is φ = 336000.

The previous prime is 721921. The next prime is 721951. The reversal of 721928 is 829127.

It is a happy number.

It is a cake number, because a cake can be divided into 721928 parts by 163 planar cuts.

It is a self number, because there is not a number n which added to its sum of digits gives 721928.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 721928.

It is not an unprimeable number, because it can be changed into a prime (721921) by changing a digit.

721928 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 7 ways as a sum of consecutive naturals, for example, 10133 + ... + 10203.

It is an arithmetic number, because the mean of its divisors is an integer number (45360).

2⁷²¹⁹²⁸ is an apocalyptic number.

It is an amenable number.

721928 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.

721928 is a wasteful number, since it uses less digits than its factorization.

721928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149 (or 145 counting only the distinct ones).

The product of its digits is 2016, while the sum is 29.

The square root of 721928 is about 849.6634627898. The cubic root of 721928 is about 89.7080250022.

The spelling of 721928 in words is "seven hundred twenty-one thousand, nine hundred twenty-eight".