81943868160 has 1728 divisors, whose sum is σ = 380505807360. Its totient is φ = 16504750080.

The previous prime is 81943868159. The next prime is 81943868177. The reversal of 81943868160 is 6186834918.

It is a tau number, because it is divible by the number of its divisors (1728).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a junction number, because it is equal to n+sod(n) for n = 81943868097 and 81943868106.

It is a congruent number.

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 191 ways as a sum of consecutive naturals, for example, 987275479 + ... + 987275561.

It is an arithmetic number, because the mean of its divisors is an integer number (220200120).

Almost surely, 2^81943868160 is an apocalyptic number.

81943868160 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 81943868160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (190252903680).

81943868160 is an abundant number, since it is smaller than the sum of its proper divisors (298561939200).

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

81943868160 is a wasteful number, since it uses less digits than its factorization.

81943868160 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191 (or 164 counting only the distinct ones).

The product of its (nonzero) digits is 1990656, while the sum is 54.

The spelling of 81943868160 in words is "eighty-one billion, nine hundred forty-three million, eight hundred sixty-eight thousand, one hundred sixty".