865320787989 has 24 divisors (see below), whose sum is σ = 1429865254272. Its totient is φ = 493984686240.

The previous prime is 865320787939. The next prime is 865320787999. The reversal of 865320787989 is 989787023568.

865320787989 is a `hidden beast` number, since 8 + 6 + 532 + 0 + 7 + 8 + 7 + 9 + 89 = 666.

It is not a de Polignac number, because 865320787989 - 2⁹ = 865320787477 is a prime.

It is a super-2 number, since 2×865320787989² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (865320787939) 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 23 ways as a sum of consecutive naturals, for example, 6662049 + ... + 6790694.

It is an arithmetic number, because the mean of its divisors is an integer number (59577718928).

Almost surely, 2^865320787989 is an apocalyptic number.

It is an amenable number.

865320787989 is a deficient number, since it is larger than the sum of its proper divisors (564544466283).

865320787989 is a wasteful number, since it uses less digits than its factorization.

865320787989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13453777 (or 13453774 counting only the distinct ones).

The product of its (nonzero) digits is 365783040, while the sum is 72.

The spelling of 865320787989 in words is "eight hundred sixty-five billion, three hundred twenty million, seven hundred eighty-seven thousand, nine hundred eighty-nine".