809728 has 18 divisors (see below), whose sum is σ = 1616804. Its totient is φ = 404736.

The previous prime is 809719. The next prime is 809729. The reversal of 809728 is 827908.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 809693 and 809702.

It is not an unprimeable number, because it can be changed into a prime (809729) by changing a digit.

809728 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 (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1326 + ... + 1837.

2⁸⁰⁹⁷²⁸ is an apocalyptic number.

It is an amenable number.

809728 is a deficient number, since it is larger than the sum of its proper divisors (807076).

809728 is an equidigital number, since it uses as much as digits as its factorization.

809728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3179 (or 3165 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 34.

The square root of 809728 is about 899.8488762009. The cubic root of 809728 is about 93.2065398470.

The spelling of 809728 in words is "eight hundred nine thousand, seven hundred twenty-eight".