81936863270472 has 256 divisors, whose sum is σ = 237339111260160. Its totient is φ = 23089646813184.

The previous prime is 81936863270419. The next prime is 81936863270491. The reversal of 81936863270472 is 27407236863918.

It is a Smith number, since the sum of its digits (66) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 3196525368 + ... + 3196551000.

It is an arithmetic number, because the mean of its divisors is an integer number (927105903360).

Almost surely, 2^{81936863270472} 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 81936863270472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (118669555630080).

81936863270472 is an abundant number, since it is smaller than the sum of its proper divisors (155402247989688).

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

81936863270472 is a wasteful number, since it uses less digits than its factorization.

81936863270472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26652 (or 26648 counting only the distinct ones).

The product of its (nonzero) digits is 146313216, while the sum is 66.

The spelling of 81936863270472 in words is "eighty-one trillion, nine hundred thirty-six billion, eight hundred sixty-three million, two hundred seventy thousand, four hundred seventy-two".