81571189432329 has 81 divisors (see below), whose sum is σ = 123040995352821. Its totient is φ = 52074481979520.

The previous prime is 81571189432283. The next prime is 81571189432333. The reversal of 81571189432329 is 92323498117518.

It is a happy number.

The square root of 81571189432329 is 9031677.

It is a perfect power (a square), and thus also a powerful number.

81571189432329 is a `hidden beast` number, since 8 + 1 + 57 + 118 + 9 + 432 + 32 + 9 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 36940078287225 + 44631111145104 = 6077835^2 + 6680652^2 .

It is not a de Polignac number, because 81571189432329 - 2¹⁷ = 81571189301257 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81571189432399) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 61749574989 + ... + 61749576309.

Almost surely, 2^{81571189432329} is an apocalyptic number.

81571189432329 is the 9031677-th square number.

81571189432329 is the 4515839-th centered octagonal number.

It is an amenable number.

81571189432329 is a deficient number, since it is larger than the sum of its proper divisors (41469805920492).

81571189432329 is an frugal number, since it uses more digits than its factorization.

81571189432329 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2840 (or 1420 counting only the distinct ones).

The product of its digits is 26127360, while the sum is 63.

The spelling of 81571189432329 in words is "eighty-one trillion, five hundred seventy-one billion, one hundred eighty-nine million, four hundred thirty-two thousand, three hundred twenty-nine".