861084864 has 112 divisors (see below), whose sum is σ = 2664764800. Its totient is φ = 271911168.

The previous prime is 861084853. The next prime is 861084929. The reversal of 861084864 is 468480168.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19719 + ... + 45945.

Almost surely, 2^861084864 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 861084864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1332382400).

861084864 is an abundant number, since it is smaller than the sum of its proper divisors (1803679936).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

861084864 is a wasteful number, since it uses less digits than its factorization.

861084864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26267 (or 26251 counting only the distinct ones).

The product of its (nonzero) digits is 294912, while the sum is 45.

The square root of 861084864 is about 29344.2475453026. The cubic root of 861084864 is about 951.3682459693.

The spelling of 861084864 in words is "eight hundred sixty-one million, eighty-four thousand, eight hundred sixty-four".