728000821 has 4 divisors (see below), whose sum is σ = 729067392. Its totient is φ = 726934252.

The previous prime is 728000783. The next prime is 728000831. The reversal of 728000821 is 128000827.

728000821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 728000821 - 2⁹ = 728000309 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 728000821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (728000831) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 532261 + ... + 533626.

It is an arithmetic number, because the mean of its divisors is an integer number (182266848).

Almost surely, 2^728000821 is an apocalyptic number.

It is an amenable number.

728000821 is a deficient number, since it is larger than the sum of its proper divisors (1066571).

728000821 is a wasteful number, since it uses less digits than its factorization.

728000821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1066570.

The product of its (nonzero) digits is 1792, while the sum is 28.

The square root of 728000821 is about 26981.4903406020. The cubic root of 728000821 is about 899.5886272244.

The spelling of 728000821 in words is "seven hundred twenty-eight million, eight hundred twenty-one", and thus it is an aban number.