866815 has 8 divisors (see below), whose sum is σ = 1060128. Its totient is φ = 680160.

The previous prime is 866783. The next prime is 866819. The reversal of 866815 is 518668.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 866815 - 2⁵ = 866783 is a prime.

It is a Duffinian number.

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 7 ways as a sum of consecutive naturals, for example, 1371 + ... + 1900.

It is an arithmetic number, because the mean of its divisors is an integer number (132516).

2⁸⁶⁶⁸¹⁵ is an apocalyptic number.

866815 is a deficient number, since it is larger than the sum of its proper divisors (193313).

866815 is a wasteful number, since it uses less digits than its factorization.

866815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3329.

The product of its digits is 11520, while the sum is 34.

The square root of 866815 is about 931.0290006224. The cubic root of 866815 is about 95.3473892696.

It can be divided in two parts, 866 and 815, that added together give a square (1681 = 41²).

The spelling of 866815 in words is "eight hundred sixty-six thousand, eight hundred fifteen".