861786806511 has 4 divisors (see below), whose sum is σ = 1149049075352. Its totient is φ = 574524537672.

The previous prime is 861786806473. The next prime is 861786806521. The reversal of 861786806511 is 115608687168.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 861786806511 - 2²⁶ = 861719697647 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 (861786806521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 143631134416 + ... + 143631134421.

It is an arithmetic number, because the mean of its divisors is an integer number (287262268838).

Almost surely, 2^861786806511 is an apocalyptic number.

861786806511 is a deficient number, since it is larger than the sum of its proper divisors (287262268841).

861786806511 is a wasteful number, since it uses less digits than its factorization.

861786806511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 287262268840.

The product of its (nonzero) digits is 3870720, while the sum is 57.

The spelling of 861786806511 in words is "eight hundred sixty-one billion, seven hundred eighty-six million, eight hundred six thousand, five hundred eleven".