861888 has 42 divisors (see below), whose sum is σ = 2314956. Its totient is φ = 283008.

The previous prime is 861881. The next prime is 861899. The reversal of 861888 is 888168.

It is a happy number.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (861881) by changing a digit.

861888 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 5 ways as a sum of consecutive naturals, for example, 12831 + ... + 12897.

It is an arithmetic number, because the mean of its divisors is an integer number (55118).

2⁸⁶¹⁸⁸⁸ 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 861888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1157478).

861888 is an abundant number, since it is smaller than the sum of its proper divisors (1453068).

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

861888 is an equidigital number, since it uses as much as digits as its factorization.

861888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149 (or 72 counting only the distinct ones).

The product of its digits is 24576, while the sum is 39.

The square root of 861888 is about 928.3792328569. The cubic root of 861888 is about 95.1663935237.

The spelling of 861888 in words is "eight hundred sixty-one thousand, eight hundred eighty-eight".