864553521 has 16 divisors (see below), whose sum is σ = 1242206336. Its totient is φ = 531691776.

The previous prime is 864553363. The next prime is 864553537. The reversal of 864553521 is 125355468.

It is not a de Polignac number, because 864553521 - 2⁹ = 864553009 is a prime.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 864553521.

It is not an unprimeable number, because it can be changed into a prime (864553021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 63321 + ... + 75753.

It is an arithmetic number, because the mean of its divisors is an integer number (77637896).

Almost surely, 2^864553521 is an apocalyptic number.

It is an amenable number.

864553521 is a deficient number, since it is larger than the sum of its proper divisors (377652815).

864553521 is a wasteful number, since it uses less digits than its factorization.

864553521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14232.

The product of its digits is 144000, while the sum is 39.

The square root of 864553521 is about 29403.2909892753. The cubic root of 864553521 is about 952.6439812381.

The spelling of 864553521 in words is "eight hundred sixty-four million, five hundred fifty-three thousand, five hundred twenty-one".