861880 has 32 divisors (see below), whose sum is σ = 2008800. Its totient is φ = 332416.

The previous prime is 861877. The next prime is 861881. The reversal of 861880 is 88168.

861880 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861881) 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, 789 + ... + 1531.

It is an arithmetic number, because the mean of its divisors is an integer number (62775).

2⁸⁶¹⁸⁸⁰ 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 861880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1004400).

861880 is an abundant number, since it is smaller than the sum of its proper divisors (1146920).

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

861880 is a wasteful number, since it uses less digits than its factorization.

861880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 783 (or 779 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 31.

The square root of 861880 is about 928.3749242628. The cubic root of 861880 is about 95.1660990796.

The spelling of 861880 in words is "eight hundred sixty-one thousand, eight hundred eighty".