861123308985 has 12 divisors (see below), whose sum is σ = 1492613735652. Its totient is φ = 459265764768.

The previous prime is 861123308911. The next prime is 861123309001. The reversal of 861123308985 is 589803321168.

It can be written as a sum of positive squares in 2 ways, for example, as 168726242169 + 692397066816 = 410763^2 + 832104^2 .

It is a de Polignac number, because none of the positive numbers 2^k-861123308985 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9568036722 + ... + 9568036811.

It is an arithmetic number, because the mean of its divisors is an integer number (124384477971).

Almost surely, 2^861123308985 is an apocalyptic number.

It is an amenable number.

861123308985 is a deficient number, since it is larger than the sum of its proper divisors (631490426667).

861123308985 is a wasteful number, since it uses less digits than its factorization.

861123308985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19136073544 (or 19136073541 counting only the distinct ones).

The product of its (nonzero) digits is 2488320, while the sum is 54.

The spelling of 861123308985 in words is "eight hundred sixty-one billion, one hundred twenty-three million, three hundred eight thousand, nine hundred eighty-five".