81408108992 has 168 divisors, whose sum is σ = 192047884128. Its totient is φ = 33537853440.

The previous prime is 81408108967. The next prime is 81408109063. The reversal of 81408108992 is 29980180418.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 81408108992.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 74480798 + ... + 74481890.

Almost surely, 2^81408108992 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 81408108992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (96023942064).

81408108992 is an abundant number, since it is smaller than the sum of its proper divisors (110639775136).

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

81408108992 is a wasteful number, since it uses less digits than its factorization.

81408108992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1347 (or 1306 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 50.

The spelling of 81408108992 in words is "eighty-one billion, four hundred eight million, one hundred eight thousand, nine hundred ninety-two".