866091 has 4 divisors (see below), whose sum is σ = 1154792. Its totient is φ = 577392.

The previous prime is 866087. The next prime is 866093. The reversal of 866091 is 190668.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 866091 - 2² = 866087 is a prime.

It is a super-2 number, since 2×866091² = 1500227240562, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (866093) 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, 144346 + ... + 144351.

It is an arithmetic number, because the mean of its divisors is an integer number (288698).

2⁸⁶⁶⁰⁹¹ is an apocalyptic number.

866091 is a deficient number, since it is larger than the sum of its proper divisors (288701).

866091 is a wasteful number, since it uses less digits than its factorization.

866091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 288700.

The product of its (nonzero) digits is 2592, while the sum is 30.

The square root of 866091 is about 930.6401022952. The cubic root of 866091 is about 95.3208358382.

The spelling of 866091 in words is "eight hundred sixty-six thousand, ninety-one".