820804 has 6 divisors (see below), whose sum is σ = 1436414. Its totient is φ = 410400.

The previous prime is 820793. The next prime is 820837. The reversal of 820804 is 408028.

It can be written as a sum of positive squares in only one way, i.e., 806404 + 14400 = 898^2 + 120^2 .

It is a nialpdrome in base 16.

It is an unprimeable number.

820804 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, 102597 + ... + 102604.

2⁸²⁰⁸⁰⁴ is an apocalyptic number.

It is an amenable number.

820804 is a deficient number, since it is larger than the sum of its proper divisors (615610).

820804 is a wasteful number, since it uses less digits than its factorization.

820804 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 205205 (or 205203 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 22.

The square root of 820804 is about 905.9823397837. The cubic root of 820804 is about 93.6295971368.

The spelling of 820804 in words is "eight hundred twenty thousand, eight hundred four".