81589027992 has 128 divisors (see below), whose sum is σ = 216531168000. Its totient is φ = 25546959360.

The previous prime is 81589027991. The next prime is 81589028009. The reversal of 81589027992 is 29972098518.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81589027991) 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 31 ways as a sum of consecutive naturals, for example, 40210434 + ... + 40212462.

It is an arithmetic number, because the mean of its divisors is an integer number (1691649750).

Almost surely, 2^81589027992 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 81589027992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108265584000).

81589027992 is an abundant number, since it is smaller than the sum of its proper divisors (134942140008).

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

81589027992 is a wasteful number, since it uses less digits than its factorization.

81589027992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2761 (or 2757 counting only the distinct ones).

The product of its (nonzero) digits is 6531840, while the sum is 60.

The spelling of 81589027992 in words is "eighty-one billion, five hundred eighty-nine million, twenty-seven thousand, nine hundred ninety-two".