864521 has 4 divisors (see below), whose sum is σ = 988032. Its totient is φ = 741012.

The previous prime is 864511. The next prime is 864533. The reversal of 864521 is 125468.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 864521 - 2¹⁰ = 863497 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (864511) 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, 61745 + ... + 61758.

It is an arithmetic number, because the mean of its divisors is an integer number (247008).

2⁸⁶⁴⁵²¹ is an apocalyptic number.

It is an amenable number.

864521 is a deficient number, since it is larger than the sum of its proper divisors (123511).

864521 is a wasteful number, since it uses less digits than its factorization.

864521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123510.

The product of its digits is 1920, while the sum is 26.

The square root of 864521 is about 929.7962142319. The cubic root of 864521 is about 95.2632036220.

Adding to 864521 its reverse (125468), we get a palindrome (989989).

The spelling of 864521 in words is "eight hundred sixty-four thousand, five hundred twenty-one".