864611920 has 20 divisors (see below), whose sum is σ = 2010222900. Its totient is φ = 345844736.

The previous prime is 864611903. The next prime is 864611933. The reversal of 864611920 is 29116468.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 342398016 + 522213904 = 18504^2 + 22852^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a self number, because there is not a number n which added to its sum of digits gives 864611920.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5403745 + ... + 5403904.

It is an arithmetic number, because the mean of its divisors is an integer number (100511145).

Almost surely, 2^864611920 is an apocalyptic number.

864611920 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

864611920 is an abundant number, since it is smaller than the sum of its proper divisors (1145610980).

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

864611920 is a wasteful number, since it uses less digits than its factorization.

864611920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10807662 (or 10807656 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 37.

The square root of 864611920 is about 29404.2840416154. The cubic root of 864611920 is about 952.6654305380.

The spelling of 864611920 in words is "eight hundred sixty-four million, six hundred eleven thousand, nine hundred twenty".