864187840 has 56 divisors (see below), whose sum is σ = 2076145200. Its totient is φ = 342601728.

The previous prime is 864187823. The next prime is 864187853. The reversal of 864187840 is 48781468.

It is a happy number.

It is a congruent number.

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 7 ways as a sum of consecutive naturals, for example, 24211 + ... + 48109.

Almost surely, 2^864187840 is an apocalyptic number.

864187840 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 864187840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1038072600).

864187840 is an abundant number, since it is smaller than the sum of its proper divisors (1211957360).

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

864187840 is a wasteful number, since it uses less digits than its factorization.

864187840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24029 (or 24019 counting only the distinct ones).

The product of its (nonzero) digits is 344064, while the sum is 46.

The square root of 864187840 is about 29397.0719630374. The cubic root of 864187840 is about 952.5096487290.

The spelling of 864187840 in words is "eight hundred sixty-four million, one hundred eighty-seven thousand, eight hundred forty".