864939 has 4 divisors (see below), whose sum is σ = 1153256. Its totient is φ = 576624.

The previous prime is 864917. The next prime is 864947. The reversal of 864939 is 939468.

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

It is not a de Polignac number, because 864939 - 2⁷ = 864811 is a prime.

It is a D-number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 864897 and 864906.

It is not an unprimeable number, because it can be changed into a prime (864959) 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 3 ways as a sum of consecutive naturals, for example, 144154 + ... + 144159.

It is an arithmetic number, because the mean of its divisors is an integer number (288314).

2⁸⁶⁴⁹³⁹ is an apocalyptic number.

864939 is a deficient number, since it is larger than the sum of its proper divisors (288317).

864939 is a wasteful number, since it uses less digits than its factorization.

864939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 288316.

The product of its digits is 46656, while the sum is 39.

The square root of 864939 is about 930.0209675056. The cubic root of 864939 is about 95.2785545516.

Subtracting from 864939 its sum of digits (39), we obtain a square (864900 = 930²).

Subtracting 864939 from its reverse (939468), we obtain a square (74529 = 273²).

The spelling of 864939 in words is "eight hundred sixty-four thousand, nine hundred thirty-nine".