81009194112 has 288 divisors, whose sum is σ = 292838931840. Its totient is φ = 21041095680.

The previous prime is 81009194081. The next prime is 81009194137. The reversal of 81009194112 is 21149190018.

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

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 934233 + ... + 1017255.

Almost surely, 2^81009194112 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 81009194112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (146419465920).

81009194112 is an abundant number, since it is smaller than the sum of its proper divisors (211829737728).

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

81009194112 is a wasteful number, since it uses less digits than its factorization.

81009194112 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83072 (or 83046 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 36.

The spelling of 81009194112 in words is "eighty-one billion, nine million, one hundred ninety-four thousand, one hundred twelve".