861589945240 has 64 divisors (see below), whose sum is σ = 2003150684160. Its totient is φ = 333178930560.

The previous prime is 861589945093. The next prime is 861589945241. The reversal of 861589945240 is 42549985168.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861589945241) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 865497 + ... + 1572343.

It is an arithmetic number, because the mean of its divisors is an integer number (31299229440).

Almost surely, 2^861589945240 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 861589945240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1001575342080).

861589945240 is an abundant number, since it is smaller than the sum of its proper divisors (1141560738920).

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

861589945240 is a wasteful number, since it uses less digits than its factorization.

861589945240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 707872 (or 707868 counting only the distinct ones).

The product of its (nonzero) digits is 24883200, while the sum is 61.

The spelling of 861589945240 in words is "eight hundred sixty-one billion, five hundred eighty-nine million, nine hundred forty-five thousand, two hundred forty".