866691 has 12 divisors (see below), whose sum is σ = 1430832. Its totient is φ = 495216.

The previous prime is 866689. The next prime is 866693. The reversal of 866691 is 196668.

866691 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (866689) and next prime (866693).

It is not a de Polignac number, because 866691 - 2¹ = 866689 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (866693) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6816 + ... + 6941.

It is an arithmetic number, because the mean of its divisors is an integer number (119236).

2⁸⁶⁶⁶⁹¹ is an apocalyptic number.

866691 is a deficient number, since it is larger than the sum of its proper divisors (564141).

866691 is a wasteful number, since it uses less digits than its factorization.

866691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13770 (or 13767 counting only the distinct ones).

The product of its digits is 15552, while the sum is 36.

The square root of 866691 is about 930.9624052560. The cubic root of 866691 is about 95.3428424940.

The spelling of 866691 in words is "eight hundred sixty-six thousand, six hundred ninety-one".