81181632540736 has 224 divisors, whose sum is σ = 208817896734720. Its totient is φ = 30409165670400.

The previous prime is 81181632540677. The next prime is 81181632540859. The reversal of 81181632540736 is 63704523618118.

It is a tau number, because it is divible by the number of its divisors (224).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 206841321 + ... + 207233431.

It is an arithmetic number, because the mean of its divisors is an integer number (932222753280).

Almost surely, 2^{81181632540736} 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 81181632540736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (104408948367360).

81181632540736 is an abundant number, since it is smaller than the sum of its proper divisors (127636264193984).

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

81181632540736 is a wasteful number, since it uses less digits than its factorization.

81181632540736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 394033 (or 394023 counting only the distinct ones).

The product of its (nonzero) digits is 5806080, while the sum is 55.

The spelling of 81181632540736 in words is "eighty-one trillion, one hundred eighty-one billion, six hundred thirty-two million, five hundred forty thousand, seven hundred thirty-six".