81934017984 has 1344 divisors, whose sum is σ = 328403712000. Its totient is φ = 19313344512.

The previous prime is 81934017967. The next prime is 81934018027. The reversal of 81934017984 is 48971043918.

81934017984 is a `hidden beast` number, since 8 + 1 + 93 + 401 + 79 + 84 = 666.

It is a tau number, because it is divible by the number of its divisors (1344).

It is a self number, because there is not a number n which added to its sum of digits gives 81934017984.

It is a congruent number.

It is an unprimeable number.

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 191 ways as a sum of consecutive naturals, for example, 1122383772 + ... + 1122383844.

It is an arithmetic number, because the mean of its divisors is an integer number (244348000).

Almost surely, 2^81934017984 is an apocalyptic number.

81934017984 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 81934017984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (164201856000).

81934017984 is an abundant number, since it is smaller than the sum of its proper divisors (246469694016).

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

81934017984 is a wasteful number, since it uses less digits than its factorization.

81934017984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167 (or 140 counting only the distinct ones).

The product of its (nonzero) digits is 1741824, while the sum is 54.

The spelling of 81934017984 in words is "eighty-one billion, nine hundred thirty-four million, seventeen thousand, nine hundred eighty-four".