720928 has 24 divisors (see below), whose sum is σ = 1529388. Its totient is φ = 332544.

The previous prime is 720913. The next prime is 720931. The reversal of 720928 is 829027.

It can be written as a sum of positive squares in 2 ways, for example, as 685584 + 35344 = 828^2 + 188^2 .

It is a Smith number, since the sum of its digits (28) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 720896 and 720905.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 451 + ... + 1282.

2⁷²⁰⁹²⁸ is an apocalyptic number.

It is an amenable number.

720928 is an abundant number, since it is smaller than the sum of its proper divisors (808460).

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

720928 is a wasteful number, since it uses less digits than its factorization.

720928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1756 (or 1748 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 720928 is about 849.0747905809. The cubic root of 720928 is about 89.6665852845. Note that the first 3 decimals are identical.

The spelling of 720928 in words is "seven hundred twenty thousand, nine hundred twenty-eight".