861881800 has 192 divisors, whose sum is σ = 2312352000. Its totient is φ = 296110080.

The previous prime is 861881791. The next prime is 861881803. The reversal of 861881800 is 8188168.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is not an unprimeable number, because it can be changed into a prime (861881803) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3606081 + ... + 3606319.

It is an arithmetic number, because the mean of its divisors is an integer number (12043500).

Almost surely, 2^861881800 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 861881800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1156176000).

861881800 is an abundant number, since it is smaller than the sum of its proper divisors (1450470200).

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

861881800 is a wasteful number, since it uses less digits than its factorization.

861881800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 360 (or 351 counting only the distinct ones).

The product of its (nonzero) digits is 24576, while the sum is 40.

The square root of 861881800 is about 29357.8234888079. The cubic root of 861881800 is about 951.6616532967.

The spelling of 861881800 in words is "eight hundred sixty-one million, eight hundred eighty-one thousand, eight hundred".