865949889605 has 18 divisors (see below), whose sum is σ = 1043555663094. Its totient is φ = 689828473600.

The previous prime is 865949889589. The next prime is 865949889647. The reversal of 865949889605 is 506988949568.

It can be written as a sum of positive squares in 9 ways, for example, as 105288568324 + 760661321281 = 324482^2 + 872159^2 .

It is not a de Polignac number, because 865949889605 - 2⁴ = 865949889589 is a prime.

It is a super-2 number, since 2×865949889605² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 584705465 + ... + 584706945.

Almost surely, 2^865949889605 is an apocalyptic number.

It is an amenable number.

865949889605 is a deficient number, since it is larger than the sum of its proper divisors (177605773489).

865949889605 is an frugal number, since it uses more digits than its factorization.

865949889605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3529 (or 1767 counting only the distinct ones).

The product of its (nonzero) digits is 1343692800, while the sum is 77.

The spelling of 865949889605 in words is "eight hundred sixty-five billion, nine hundred forty-nine million, eight hundred eighty-nine thousand, six hundred five".