81907672128 has 448 divisors, whose sum is σ = 246176962560. Its totient is φ = 23911759872.

The previous prime is 81907672087. The next prime is 81907672129. The reversal of 81907672128 is 82127670918.

It is not an unprimeable number, because it can be changed into a prime (81907672129) by changing a digit.

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 63 ways as a sum of consecutive naturals, for example, 502500975 + ... + 502501137.

Almost surely, 2^81907672128 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 81907672128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (123088481280).

81907672128 is an abundant number, since it is smaller than the sum of its proper divisors (164269290432).

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

81907672128 is a wasteful number, since it uses less digits than its factorization.

81907672128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 386 (or 376 counting only the distinct ones).

The product of its (nonzero) digits is 677376, while the sum is 51.

The spelling of 81907672128 in words is "eighty-one billion, nine hundred seven million, six hundred seventy-two thousand, one hundred twenty-eight".