866989 has 4 divisors (see below), whose sum is σ = 912640. Its totient is φ = 821340.

The previous prime is 866969. The next prime is 867001. The reversal of 866989 is 989668.

It is a happy number.

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 866989 - 2⁹ = 866477 is a prime.

It is a super-2 number, since 2×866989² = 1503339852242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (866909) 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, 22797 + ... + 22834.

It is an arithmetic number, because the mean of its divisors is an integer number (228160).

2⁸⁶⁶⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

866989 is a deficient number, since it is larger than the sum of its proper divisors (45651).

866989 is a wasteful number, since it uses less digits than its factorization.

866989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45650.

The product of its digits is 186624, while the sum is 46.

The square root of 866989 is about 931.1224409282. The cubic root of 866989 is about 95.3537686915.

The spelling of 866989 in words is "eight hundred sixty-six thousand, nine hundred eighty-nine".