81516999763584 has 1024 divisors, whose sum is σ = 317800143360000. Its totient is φ = 19915124244480.

The previous prime is 81516999763553. The next prime is 81516999763691. The reversal of 81516999763584 is 48536799961518.

81516999763584 is a `hidden beast` number, since 8 + 1 + 51 + 69 + 99 + 76 + 358 + 4 = 666.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 8545649887 + ... + 8545659425.

It is an arithmetic number, because the mean of its divisors is an integer number (310351702500).

Almost surely, 2^{81516999763584} is an apocalyptic number.

81516999763584 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81516999763584, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (158900071680000).

81516999763584 is an abundant number, since it is smaller than the sum of its proper divisors (236283143596416).

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

81516999763584 is a wasteful number, since it uses less digits than its factorization.

81516999763584 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11486 (or 11468 counting only the distinct ones).

The product of its digits is 3527193600, while the sum is 81.

The spelling of 81516999763584 in words is "eighty-one trillion, five hundred sixteen billion, nine hundred ninety-nine million, seven hundred sixty-three thousand, five hundred eighty-four".