815868 has 36 divisors (see below), whose sum is σ = 2090088. Its totient is φ = 268320.

The previous prime is 815851. The next prime is 815869. The reversal of 815868 is 868518.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (815869) by changing a digit.

815868 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4630 + ... + 4802.

It is an arithmetic number, because the mean of its divisors is an integer number (58058).

2⁸¹⁵⁸⁶⁸ is an apocalyptic number.

It is an amenable number.

815868 is an abundant number, since it is smaller than the sum of its proper divisors (1274220).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

815868 is a wasteful number, since it uses less digits than its factorization.

815868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 314 (or 309 counting only the distinct ones).

The product of its digits is 15360, while the sum is 36.

The square root of 815868 is about 903.2541170678. The cubic root of 815868 is about 93.4415355095.

Subtracting 815868 from its reverse (868518), we obtain a triangular number (52650 = T₃₂₄).

It can be divided in two parts, 8 and 15868, that added together give a square (15876 = 126²).

The spelling of 815868 in words is "eight hundred fifteen thousand, eight hundred sixty-eight".