81816376704 has 128 divisors (see below), whose sum is σ = 218698444800. Its totient is φ = 27100286976.

The previous prime is 81816376693. The next prime is 81816376721. The reversal of 81816376704 is 40767361818.

It is a tau number, because it is divible by the number of its divisors (128).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 79202172 + ... + 79203204.

It is an arithmetic number, because the mean of its divisors is an integer number (1708581600).

Almost surely, 2^81816376704 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 81816376704, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109349222400).

81816376704 is an abundant number, since it is smaller than the sum of its proper divisors (136882068096).

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

81816376704 is a wasteful number, since it uses less digits than its factorization.

81816376704 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2152 (or 2140 counting only the distinct ones).

The product of its (nonzero) digits is 1354752, while the sum is 51.

The spelling of 81816376704 in words is "eighty-one billion, eight hundred sixteen million, three hundred seventy-six thousand, seven hundred four".