861804 has 36 divisors (see below), whose sum is σ = 2240784. Its totient is φ = 279072.

The previous prime is 861803. The next prime is 861823. The reversal of 861804 is 408168.

861804 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a super-2 number, since 2×861804² = 1485412268832, which contains 22 as substring.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 861804.

It is not an unprimeable number, because it can be changed into a prime (861803) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1009 + ... + 1655.

It is an arithmetic number, because the mean of its divisors is an integer number (62244).

2⁸⁶¹⁸⁰⁴ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 861804, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1120392).

861804 is an abundant number, since it is smaller than the sum of its proper divisors (1378980).

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

861804 is a wasteful number, since it uses less digits than its factorization.

861804 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 694 (or 689 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 861804 is about 928.3339916215. Note that the first 3 decimals coincide. The cubic root of 861804 is about 95.1633017698.

The spelling of 861804 in words is "eight hundred sixty-one thousand, eight hundred four".