81082081991 has 8 divisors (see below), whose sum is σ = 82017652464. Its totient is φ = 80149115200.

The previous prime is 81082081921. The next prime is 81082082017. The reversal of 81082081991 is 19918028018.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81082081991 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81082081921) 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 7 ways as a sum of consecutive naturals, for example, 588245 + ... + 712878.

It is an arithmetic number, because the mean of its divisors is an integer number (10252206558).

Almost surely, 2^81082081991 is an apocalyptic number.

81082081991 is a deficient number, since it is larger than the sum of its proper divisors (935570473).

81082081991 is a wasteful number, since it uses less digits than its factorization.

81082081991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1301841.

The product of its (nonzero) digits is 82944, while the sum is 47.

The spelling of 81082081991 in words is "eighty-one billion, eighty-two million, eighty-one thousand, nine hundred ninety-one".