866381 has 4 divisors (see below), whose sum is σ = 912000. Its totient is φ = 820764.

The previous prime is 866353. The next prime is 866389. The reversal of 866381 is 183668.

866381 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 866381 - 2¹⁰ = 865357 is a prime.

It is a super-2 number, since 2×866381² = 1501232074322, which contains 22 as substring.

It is a Curzon number.

It is a plaindrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (866389) 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, 22781 + ... + 22818.

It is an arithmetic number, because the mean of its divisors is an integer number (228000).

2⁸⁶⁶³⁸¹ is an apocalyptic number.

It is an amenable number.

866381 is a deficient number, since it is larger than the sum of its proper divisors (45619).

866381 is a wasteful number, since it uses less digits than its factorization.

866381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45618.

The product of its digits is 6912, while the sum is 32.

The square root of 866381 is about 930.7958959944. The cubic root of 866381 is about 95.3314736571.

The spelling of 866381 in words is "eight hundred sixty-six thousand, three hundred eighty-one".