81564737607936 has 432 divisors, whose sum is σ = 264276581325120. Its totient is φ = 23978975232000.

The previous prime is 81564737607877. The next prime is 81564737607949. The reversal of 81564737607936 is 63970673746518.

81564737607936 is a `hidden beast` number, since 8 + 1 + 5 + 6 + 4 + 7 + 3 + 7 + 607 + 9 + 3 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 185780356 + ... + 186218876.

It is an arithmetic number, because the mean of its divisors is an integer number (611751345660).

Almost surely, 2^{81564737607936} 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 81564737607936, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (132138290662560).

81564737607936 is an abundant number, since it is smaller than the sum of its proper divisors (182711843717184).

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

81564737607936 is a wasteful number, since it uses less digits than its factorization.

81564737607936 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 438774 (or 438757 counting only the distinct ones).

The product of its (nonzero) digits is 960180480, while the sum is 72.

The spelling of 81564737607936 in words is "eighty-one trillion, five hundred sixty-four billion, seven hundred thirty-seven million, six hundred seven thousand, nine hundred thirty-six".