820544881 has 4 divisors (see below), whose sum is σ = 883663732. Its totient is φ = 757426032.

The previous prime is 820544873. The next prime is 820544891. The reversal of 820544881 is 188445028.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 79834225 + 740710656 = 8935^2 + 27216^2 .

It is a cyclic number.

It is not a de Polignac number, because 820544881 - 2³ = 820544873 is a prime.

It is a super-2 number, since 2×820544881² = 1346587803470608322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (820544861) by changing a digit.

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, 31559406 + ... + 31559431.

It is an arithmetic number, because the mean of its divisors is an integer number (220915933).

Almost surely, 2^820544881 is an apocalyptic number.

It is an amenable number.

820544881 is a deficient number, since it is larger than the sum of its proper divisors (63118851).

820544881 is a wasteful number, since it uses less digits than its factorization.

820544881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63118850.

The product of its (nonzero) digits is 81920, while the sum is 40.

The square root of 820544881 is about 28645.1545815344. The cubic root of 820544881 is about 936.1974348074.

The spelling of 820544881 in words is "eight hundred twenty million, five hundred forty-four thousand, eight hundred eighty-one".