820756880 has 20 divisors (see below), whose sum is σ = 1908259932. Its totient is φ = 328302720.

The previous prime is 820756879. The next prime is 820756913. The reversal of 820756880 is 88657028.

It can be written as a sum of positive squares in 2 ways, for example, as 246866944 + 573889936 = 15712^2 + 23956^2 .

It is a tau number, because it is divible by the number of its divisors (20).

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 3 ways as a sum of consecutive naturals, for example, 5129651 + ... + 5129810.

Almost surely, 2^820756880 is an apocalyptic number.

820756880 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

820756880 is an abundant number, since it is smaller than the sum of its proper divisors (1087503052).

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

820756880 is a wasteful number, since it uses less digits than its factorization.

820756880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10259474 (or 10259468 counting only the distinct ones).

The product of its (nonzero) digits is 215040, while the sum is 44.

The square root of 820756880 is about 28648.8547764130. The cubic root of 820756880 is about 936.2780543381.

The spelling of 820756880 in words is "eight hundred twenty million, seven hundred fifty-six thousand, eight hundred eighty".