81127717128 has 256 divisors, whose sum is σ = 237850905600. Its totient is φ = 25591749120.

The previous prime is 81127717063. The next prime is 81127717159. The reversal of 81127717128 is 82171772118.

It is an unprimeable number.

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 63 ways as a sum of consecutive naturals, for example, 62071051 + ... + 62072357.

It is an arithmetic number, because the mean of its divisors is an integer number (929105100).

Almost surely, 2^81127717128 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 81127717128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (118925452800).

81127717128 is an abundant number, since it is smaller than the sum of its proper divisors (156723188472).

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

81127717128 is a wasteful number, since it uses less digits than its factorization.

81127717128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1569 (or 1559 counting only the distinct ones).

The product of its digits is 87808, while the sum is 45.

The spelling of 81127717128 in words is "eighty-one billion, one hundred twenty-seven million, seven hundred seventeen thousand, one hundred twenty-eight".