81506181120 has 896 divisors, whose sum is σ = 331338180096. Its totient is φ = 16647192576.

The previous prime is 81506181089. The next prime is 81506181143. The reversal of 81506181120 is 2118160518.

It is a tau number, because it is divible by the number of its divisors (896).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 413736862 + ... + 413737058.

It is an arithmetic number, because the mean of its divisors is an integer number (369797076).

Almost surely, 2^81506181120 is an apocalyptic number.

81506181120 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81506181120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (165669090048).

81506181120 is an abundant number, since it is smaller than the sum of its proper divisors (249831998976).

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

81506181120 is a wasteful number, since it uses less digits than its factorization.

81506181120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 288 (or 264 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 33.

The spelling of 81506181120 in words is "eighty-one billion, five hundred six million, one hundred eighty-one thousand, one hundred twenty".