861205992 has 64 divisors (see below), whose sum is σ = 2302344000. Its totient is φ = 267494400.

The previous prime is 861205927. The next prime is 861205999. The reversal of 861205992 is 299502168.

It is not an unprimeable number, because it can be changed into a prime (861205999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30759 + ... + 51657.

It is an arithmetic number, because the mean of its divisors is an integer number (35974125).

Almost surely, 2^861205992 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 861205992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1151172000).

861205992 is an abundant number, since it is smaller than the sum of its proper divisors (1441138008).

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

861205992 is a wasteful number, since it uses less digits than its factorization.

861205992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21026 (or 21022 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 42.

The square root of 861205992 is about 29346.3113866121. The cubic root of 861205992 is about 951.4128532373.

The spelling of 861205992 in words is "eight hundred sixty-one million, two hundred five thousand, nine hundred ninety-two".