81634728960 has 440 divisors, whose sum is σ = 309767269680. Its totient is φ = 20486946816.

The previous prime is 81634728941. The next prime is 81634728971. The reversal of 81634728960 is 6982743618.

81634728960 is a `hidden beast` number, since 8 + 16 + 347 + 289 + 6 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a junction number, because it is equal to n+sod(n) for n = 81634728897 and 81634728906.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 7044451 + ... + 7056029.

It is an arithmetic number, because the mean of its divisors is an integer number (704016522).

Almost surely, 2^81634728960 is an apocalyptic number.

81634728960 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 81634728960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (154883634840).

81634728960 is an abundant number, since it is smaller than the sum of its proper divisors (228132540720).

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

81634728960 is a wasteful number, since it uses less digits than its factorization.

81634728960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11633 (or 11606 counting only the distinct ones).

The product of its (nonzero) digits is 3483648, while the sum is 54.

The spelling of 81634728960 in words is "eighty-one billion, six hundred thirty-four million, seven hundred twenty-eight thousand, nine hundred sixty".