81529999439616 has 2592 divisors, whose sum is σ = 310894814438208. Its totient is φ = 20346733854720.

The previous prime is 81529999439599. The next prime is 81529999439617. The reversal of 81529999439616 is 61693499992518.

81529999439616 is a `hidden beast` number, since 8 + 1 + 5 + 2 + 99 + 99 + 439 + 6 + 1 + 6 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81529999439617) by changing a digit.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 519299359410 + ... + 519299359566.

Almost surely, 2^{81529999439616} 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 81529999439616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (155447407219104).

81529999439616 is an abundant number, since it is smaller than the sum of its proper divisors (229364814998592).

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

81529999439616 is a wasteful number, since it uses less digits than its factorization.

81529999439616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 447 (or 423 counting only the distinct ones).

The product of its digits is 2040733440, while the sum is 81.

The spelling of 81529999439616 in words is "eighty-one trillion, five hundred twenty-nine billion, nine hundred ninety-nine million, four hundred thirty-nine thousand, six hundred sixteen".