6805207511991 has 96 divisors (see below), whose sum is σ = 11645383193600. Its totient is φ = 3827018010816.

The previous prime is 6805207511983. The next prime is 6805207512007. The reversal of 6805207511991 is 1991157025086.

It is a happy number.

6805207511991 is a `hidden beast` number, since 68 + 0 + 520 + 7 + 51 + 1 + 9 + 9 + 1 = 666.

6805207511991 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 6805207511991 - 2³ = 6805207511983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6805207511491) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 226049046 + ... + 226079148.

Almost surely, 2^{6805207511991} is an apocalyptic number.

6805207511991 is a deficient number, since it is larger than the sum of its proper divisors (4840175681609).

6805207511991 is a wasteful number, since it uses less digits than its factorization.

6805207511991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31290 (or 31273 counting only the distinct ones).

The product of its (nonzero) digits is 1360800, while the sum is 54.

The spelling of 6805207511991 in words is "six trillion, eight hundred five billion, two hundred seven million, five hundred eleven thousand, nine hundred ninety-one".