866899 has 4 divisors (see below), whose sum is σ = 945720. Its totient is φ = 788080.

The previous prime is 866869. The next prime is 866909. The reversal of 866899 is 998668.

It is a happy number.

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 866899 - 2¹³ = 858707 is a prime.

It is a Duffinian number.

It is a plaindrome in base 13.

It is not an unprimeable number, because it can be changed into a prime (866819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 39394 + ... + 39415.

It is an arithmetic number, because the mean of its divisors is an integer number (236430).

2⁸⁶⁶⁸⁹⁹ is an apocalyptic number.

866899 is a deficient number, since it is larger than the sum of its proper divisors (78821).

866899 is a wasteful number, since it uses less digits than its factorization.

866899 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78820.

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

The square root of 866899 is about 931.0741109063. The cubic root of 866899 is about 95.3504690971.

Subtracting 866899 from its reverse (998668), we obtain a square (131769 = 363²).

The spelling of 866899 in words is "eight hundred sixty-six thousand, eight hundred ninety-nine".