866813 has 4 divisors (see below), whose sum is σ = 917820. Its totient is φ = 815808.

The previous prime is 866783. The next prime is 866819. The reversal of 866813 is 318668.

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

It can be written as a sum of positive squares in 2 ways, for example, as 573049 + 293764 = 757^2 + 542^2 .

It is a cyclic number.

It is not a de Polignac number, because 866813 - 2¹⁶ = 801277 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 866813.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (866819) 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, 25478 + ... + 25511.

It is an arithmetic number, because the mean of its divisors is an integer number (229455).

2⁸⁶⁶⁸¹³ is an apocalyptic number.

It is an amenable number.

866813 is a deficient number, since it is larger than the sum of its proper divisors (51007).

866813 is a wasteful number, since it uses less digits than its factorization.

866813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51006.

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

The square root of 866813 is about 931.0279265414. The cubic root of 866813 is about 95.3473159380.

The spelling of 866813 in words is "eight hundred sixty-six thousand, eight hundred thirteen".