861878 has 16 divisors (see below), whose sum is σ = 1399920. Its totient is φ = 396576.

The previous prime is 861877. The next prime is 861881. The reversal of 861878 is 878168.

It is a Harshad number since it is a multiple of its sum of digits (38).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861871) 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 7 ways as a sum of consecutive naturals, for example, 1100 + ... + 1712.

It is an arithmetic number, because the mean of its divisors is an integer number (87495).

2⁸⁶¹⁸⁷⁸ is an apocalyptic number.

861878 is a deficient number, since it is larger than the sum of its proper divisors (538042).

861878 is a wasteful number, since it uses less digits than its factorization.

861878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 671.

The product of its digits is 21504, while the sum is 38.

The square root of 861878 is about 928.3738471112. The cubic root of 861878 is about 95.1660254683.

Subtracting 861878 from its reverse (878168), we obtain a triangular number (16290 = T₁₈₀).

The spelling of 861878 in words is "eight hundred sixty-one thousand, eight hundred seventy-eight".