81059189880 has 128 divisors (see below), whose sum is σ = 257833497600. Its totient is φ = 20316506112.

The previous prime is 81059189873. The next prime is 81059189921. The reversal of 81059189880 is 8898195018.

It is a self number, because there is not a number n which added to its sum of digits gives 81059189880.

It is a congruent number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 1488981 + ... + 1542459.

It is an arithmetic number, because the mean of its divisors is an integer number (2014324200).

Almost surely, 2^81059189880 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 81059189880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (128916748800).

81059189880 is an abundant number, since it is smaller than the sum of its proper divisors (176774307720).

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

81059189880 is a wasteful number, since it uses less digits than its factorization.

81059189880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54253 (or 54249 counting only the distinct ones).

The product of its (nonzero) digits is 1658880, while the sum is 57.

The spelling of 81059189880 in words is "eighty-one billion, fifty-nine million, one hundred eighty-nine thousand, eight hundred eighty".