81261128174568 has 128 divisors (see below), whose sum is σ = 216193533926400. Its totient is φ = 25380371326464.

The previous prime is 81261128174563. The next prime is 81261128174609. The reversal of 81261128174568 is 86547182116218.

It is not an unprimeable number, because it can be changed into a prime (81261128174563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 28755021 + ... + 31454307.

It is an arithmetic number, because the mean of its divisors is an integer number (1689011983800).

Almost surely, 2^{81261128174568} 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 81261128174568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108096766963200).

81261128174568 is an abundant number, since it is smaller than the sum of its proper divisors (134932405751832).

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

81261128174568 is a wasteful number, since it uses less digits than its factorization.

81261128174568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2700039 (or 2700035 counting only the distinct ones).

The product of its digits is 10321920, while the sum is 60.

The spelling of 81261128174568 in words is "eighty-one trillion, two hundred sixty-one billion, one hundred twenty-eight million, one hundred seventy-four thousand, five hundred sixty-eight".