861788381940 has 240 divisors, whose sum is σ = 2906302291200. Its totient is φ = 213082368768.

The previous prime is 861788381891. The next prime is 861788381981. The reversal of 861788381940 is 49183887168.

861788381940 is a `hidden beast` number, since 8 + 617 + 8 + 8 + 3 + 8 + 1 + 9 + 4 + 0 = 666.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 1148806 + ... + 1744514.

It is an arithmetic number, because the mean of its divisors is an integer number (12109592880).

Almost surely, 2^861788381940 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 861788381940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1453151145600).

861788381940 is an abundant number, since it is smaller than the sum of its proper divisors (2044513909260).

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

861788381940 is a wasteful number, since it uses less digits than its factorization.

861788381940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 595796 (or 595785 counting only the distinct ones).

The product of its (nonzero) digits is 18579456, while the sum is 63.

The spelling of 861788381940 in words is "eight hundred sixty-one billion, seven hundred eighty-eight million, three hundred eighty-one thousand, nine hundred forty".