820821024 has 72 divisors (see below), whose sum is σ = 2397327660. Its totient is φ = 266208768.

The previous prime is 820821011. The next prime is 820821031. The reversal of 820821024 is 420128028.

It can be written as a sum of positive squares in 2 ways, for example, as 672468624 + 148352400 = 25932^2 + 12180^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 27859 + ... + 49170.

Almost surely, 2^820821024 is an apocalyptic number.

It is an amenable number.

820821024 is an abundant number, since it is smaller than the sum of its proper divisors (1576506636).

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

820821024 is a wasteful number, since it uses less digits than its factorization.

820821024 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77082 (or 77071 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 27.

The square root of 820821024 is about 28649.9742408261. The cubic root of 820821024 is about 936.3024444494.

The spelling of 820821024 in words is "eight hundred twenty million, eight hundred twenty-one thousand, twenty-four".