864649 has 4 divisors (see below), whose sum is σ = 885780. Its totient is φ = 843520.

The previous prime is 864641. The next prime is 864673. The reversal of 864649 is 946468.

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

It can be written as a sum of positive squares in 2 ways, for example, as 480249 + 384400 = 693^2 + 620^2 .

It is a cyclic number.

It is not a de Polignac number, because 864649 - 2³ = 864641 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (864641) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10504 + ... + 10585.

It is an arithmetic number, because the mean of its divisors is an integer number (221445).

2⁸⁶⁴⁶⁴⁹ is an apocalyptic number.

It is an amenable number.

864649 is a deficient number, since it is larger than the sum of its proper divisors (21131).

864649 is a wasteful number, since it uses less digits than its factorization.

864649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21130.

The product of its digits is 41472, while the sum is 37.

The square root of 864649 is about 929.8650439714. The cubic root of 864649 is about 95.2679049106.

The spelling of 864649 in words is "eight hundred sixty-four thousand, six hundred forty-nine".