861640687586 has 16 divisors (see below), whose sum is σ = 1478075921280. Its totient is φ = 369030180480.

The previous prime is 861640687543. The next prime is 861640687673. The reversal of 861640687586 is 685786046168.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 20344751 + ... + 20387058.

It is an arithmetic number, because the mean of its divisors is an integer number (92379745080).

Almost surely, 2^861640687586 is an apocalyptic number.

861640687586 is a deficient number, since it is larger than the sum of its proper divisors (616435233694).

861640687586 is a wasteful number, since it uses less digits than its factorization.

861640687586 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40733329.

The product of its (nonzero) digits is 92897280, while the sum is 65.

The spelling of 861640687586 in words is "eight hundred sixty-one billion, six hundred forty million, six hundred eighty-seven thousand, five hundred eighty-six".