864521939 has 4 divisors (see below), whose sum is σ = 867087624. Its totient is φ = 861956256.

The previous prime is 864521899. The next prime is 864522007. The reversal of 864521939 is 939125468.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 864521939 - 2²⁰ = 863473363 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 864521893 and 864521902.

It is not an unprimeable number, because it can be changed into a prime (864521839) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1282337 + ... + 1283010.

It is an arithmetic number, because the mean of its divisors is an integer number (216771906).

Almost surely, 2^864521939 is an apocalyptic number.

864521939 is a deficient number, since it is larger than the sum of its proper divisors (2565685).

864521939 is a wasteful number, since it uses less digits than its factorization.

864521939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2565684.

The product of its digits is 466560, while the sum is 47.

The square root of 864521939 is about 29402.7539356435. The cubic root of 864521939 is about 952.6323811201.

The spelling of 864521939 in words is "eight hundred sixty-four million, five hundred twenty-one thousand, nine hundred thirty-nine".