820305881 has 4 divisors (see below), whose sum is σ = 820503012. Its totient is φ = 820108752.

The previous prime is 820305877. The next prime is 820305917. The reversal of 820305881 is 188503028.

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 367297225 + 453008656 = 19165^2 + 21284^2 .

It is a cyclic number.

It is not a de Polignac number, because 820305881 - 2² = 820305877 is a prime.

It is a super-2 number, since 2×820305881² = 1345803476806372322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (820305821) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 92186 + ... + 100691.

It is an arithmetic number, because the mean of its divisors is an integer number (205125753).

Almost surely, 2^820305881 is an apocalyptic number.

It is an amenable number.

820305881 is a deficient number, since it is larger than the sum of its proper divisors (197131).

820305881 is a wasteful number, since it uses less digits than its factorization.

820305881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 197130.

The product of its (nonzero) digits is 15360, while the sum is 35.

The square root of 820305881 is about 28640.9825425037. The cubic root of 820305881 is about 936.1065306129.

The spelling of 820305881 in words is "eight hundred twenty million, three hundred five thousand, eight hundred eighty-one".