866791 has 4 divisors (see below), whose sum is σ = 894784. Its totient is φ = 838800.

The previous prime is 866783. The next prime is 866819. The reversal of 866791 is 197668.

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

It is a cyclic number.

It is not a de Polignac number, because 866791 - 2³ = 866783 is a prime.

866791 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 866791.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (860791) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13950 + ... + 14011.

It is an arithmetic number, because the mean of its divisors is an integer number (223696).

2⁸⁶⁶⁷⁹¹ is an apocalyptic number.

866791 is a deficient number, since it is larger than the sum of its proper divisors (27993).

866791 is a wasteful number, since it uses less digits than its factorization.

866791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27992.

The product of its digits is 18144, while the sum is 37.

The square root of 866791 is about 931.0161115684. The cubic root of 866791 is about 95.3465092824.

The spelling of 866791 in words is "eight hundred sixty-six thousand, seven hundred ninety-one".