861811911 has 6 divisors (see below), whose sum is σ = 1244839440. Its totient is φ = 574541268.

The previous prime is 861811897. The next prime is 861811913. The reversal of 861811911 is 119118168.

It is not a de Polignac number, because 861811911 - 2²¹ = 859714759 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861811913) 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, 47878431 + ... + 47878448.

It is an arithmetic number, because the mean of its divisors is an integer number (207473240).

Almost surely, 2^861811911 is an apocalyptic number.

861811911 is a deficient number, since it is larger than the sum of its proper divisors (383027529).

861811911 is a wasteful number, since it uses less digits than its factorization.

861811911 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95756885 (or 95756882 counting only the distinct ones).

The product of its digits is 3456, while the sum is 36.

The square root of 861811911 is about 29356.6331686725. The cubic root of 861811911 is about 951.6359295531.

The spelling of 861811911 in words is "eight hundred sixty-one million, eight hundred eleven thousand, nine hundred eleven".