81993796704 has 288 divisors, whose sum is σ = 259683750144. Its totient is φ = 24421662720.

The previous prime is 81993796699. The next prime is 81993796711. The reversal of 81993796704 is 40769739918.

81993796704 is a `hidden beast` number, since 8 + 199 + 379 + 6 + 70 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 8039032 + ... + 8049224.

It is an arithmetic number, because the mean of its divisors is an integer number (901679688).

Almost surely, 2^81993796704 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 81993796704, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (129841875072).

81993796704 is an abundant number, since it is smaller than the sum of its proper divisors (177689953440).

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

81993796704 is a wasteful number, since it uses less digits than its factorization.

81993796704 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10310 (or 10299 counting only the distinct ones).

The product of its (nonzero) digits is 20575296, while the sum is 63.

The spelling of 81993796704 in words is "eighty-one billion, nine hundred ninety-three million, seven hundred ninety-six thousand, seven hundred four".