865808881 has 6 divisors (see below), whose sum is σ = 1007165490. Its totient is φ = 742121856.

The previous prime is 865808869. The next prime is 865808897. The reversal of 865808881 is 188808568.

It can be written as a sum of positive squares in only one way, i.e., 793830625 + 71978256 = 28175^2 + 8484^2 .

It is not a de Polignac number, because 865808881 - 2¹¹ = 865806833 is a prime.

It is a super-2 number, since 2×865808881² = 1499250036836944322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (865808831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8834736 + ... + 8834833.

It is an arithmetic number, because the mean of its divisors is an integer number (167860915).

Almost surely, 2^865808881 is an apocalyptic number.

It is an amenable number.

865808881 is a deficient number, since it is larger than the sum of its proper divisors (141356609).

865808881 is a wasteful number, since it uses less digits than its factorization.

865808881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17669583 (or 17669576 counting only the distinct ones).

The product of its (nonzero) digits is 983040, while the sum is 52.

The square root of 865808881 is about 29424.6305159470. The cubic root of 865808881 is about 953.1048483221.

The spelling of 865808881 in words is "eight hundred sixty-five million, eight hundred eight thousand, eight hundred eighty-one".