820560256 has 64 divisors (see below), whose sum is σ = 1672130880. Its totient is φ = 400992768.

The previous prime is 820560217. The next prime is 820560283. The reversal of 820560256 is 652065028.

It is a tau number, because it is divible by the number of its divisors (64).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1397595 + ... + 1398181.

It is an arithmetic number, because the mean of its divisors is an integer number (26127045).

Almost surely, 2^820560256 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 820560256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (836065440).

820560256 is an abundant number, since it is smaller than the sum of its proper divisors (851570624).

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

820560256 is a wasteful number, since it uses less digits than its factorization.

820560256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 831 (or 819 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 34.

The square root of 820560256 is about 28645.4229502725. The cubic root of 820560256 is about 936.2032821193.

The spelling of 820560256 in words is "eight hundred twenty million, five hundred sixty thousand, two hundred fifty-six".