866921 has 8 divisors (see below), whose sum is σ = 964224. Its totient is φ = 772720.

The previous prime is 866917. The next prime is 866927. The reversal of 866921 is 129668.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 866921 - 2² = 866917 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 866921.

It is not an unprimeable number, because it can be changed into a prime (866927) 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 7 ways as a sum of consecutive naturals, for example, 161 + ... + 1326.

It is an arithmetic number, because the mean of its divisors is an integer number (120528).

2⁸⁶⁶⁹²¹ is an apocalyptic number.

It is an amenable number.

866921 is a deficient number, since it is larger than the sum of its proper divisors (97303).

866921 is a wasteful number, since it uses less digits than its factorization.

866921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1551.

The product of its digits is 5184, while the sum is 32.

The square root of 866921 is about 931.0859251433. The cubic root of 866921 is about 95.3512756857.

It can be divided in two parts, 86 and 6921, that added together give a palindrome (7007).

The spelling of 866921 in words is "eight hundred sixty-six thousand, nine hundred twenty-one".