81505328960 has 224 divisors, whose sum is σ = 220400538624. Its totient is φ = 28677580800.

The previous prime is 81505328941. The next prime is 81505328963. The reversal of 81505328960 is 6982350518.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81505328963) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 13200434 + ... + 13206606.

It is an arithmetic number, because the mean of its divisors is an integer number (983930976).

Almost surely, 2^81505328960 is an apocalyptic number.

81505328960 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 81505328960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (110200269312).

81505328960 is an abundant number, since it is smaller than the sum of its proper divisors (138895209664).

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

81505328960 is a wasteful number, since it uses less digits than its factorization.

81505328960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6254 (or 6222 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 47.

The spelling of 81505328960 in words is "eighty-one billion, five hundred five million, three hundred twenty-eight thousand, nine hundred sixty".