720828 has 18 divisors (see below), whose sum is σ = 1822184. Its totient is φ = 240264.

The previous prime is 720793. The next prime is 720829. The reversal of 720828 is 828027.

It is a tau number, because it is divible by the number of its divisors (18).

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 720828.

It is not an unprimeable number, because it can be changed into a prime (720829) by changing a digit.

720828 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 9976 + ... + 10047.

2⁷²⁰⁸²⁸ is an apocalyptic number.

It is an amenable number.

720828 is an abundant number, since it is smaller than the sum of its proper divisors (1101356).

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

720828 is a wasteful number, since it uses less digits than its factorization.

720828 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20033 (or 20028 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 27.

The square root of 720828 is about 849.0159009112. The cubic root of 720828 is about 89.6624392056.

Subtracting from 720828 its sum of digits (27), we obtain a square (720801 = 849²).

The spelling of 720828 in words is "seven hundred twenty thousand, eight hundred twenty-eight".