81116528640 has 456 divisors, whose sum is σ = 302668787952. Its totient is φ = 18496880640.

The previous prime is 81116528629. The next prime is 81116528641. The reversal of 81116528640 is 4682561118.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 81116528592 and 81116528601.

It is not an unprimeable number, because it can be changed into a prime (81116528641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 192675630 + ... + 192676050.

It is an arithmetic number, because the mean of its divisors is an integer number (663747342).

Almost surely, 2^81116528640 is an apocalyptic number.

81116528640 is a gapful number since it is divisible by the number (80) 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 81116528640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (151334393976).

81116528640 is an abundant number, since it is smaller than the sum of its proper divisors (221552259312).

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

81116528640 is an frugal number, since it uses more digits than its factorization.

81116528640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 479 (or 438 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 42.

The spelling of 81116528640 in words is "eighty-one billion, one hundred sixteen million, five hundred twenty-eight thousand, six hundred forty".