81108668801664 has 576 divisors, whose sum is σ = 286176338229600. Its totient is φ = 22793979156480.

The previous prime is 81108668801663. The next prime is 81108668801687. The reversal of 81108668801664 is 46610886680118.

81108668801664 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (576).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (81108668801663) by changing a digit.

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 71 ways as a sum of consecutive naturals, for example, 92533647 + ... + 93406065.

Almost surely, 2^{81108668801664} is an apocalyptic number.

81108668801664 is a gapful number since it is divisible by the number (84) 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 81108668801664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (143088169114800).

81108668801664 is an abundant number, since it is smaller than the sum of its proper divisors (205067669427936).

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

81108668801664 is an equidigital number, since it uses as much as digits as its factorization.

81108668801664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 872523 (or 872492 counting only the distinct ones).

The product of its (nonzero) digits is 21233664, while the sum is 63.

The spelling of 81108668801664 in words is "eighty-one trillion, one hundred eight billion, six hundred sixty-eight million, eight hundred one thousand, six hundred sixty-four".