81175205329 has 4 divisors (see below), whose sum is σ = 81189360484. Its totient is φ = 81161050176.

The previous prime is 81175205317. The next prime is 81175205359. The reversal of 81175205329 is 92350257118.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 25905546304 + 55269659025 = 160952^2 + 235095^2 .

It is a cyclic number.

It is not a de Polignac number, because 81175205329 - 2⁵ = 81175205297 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81175205359) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7068972 + ... + 7080445.

It is an arithmetic number, because the mean of its divisors is an integer number (20297340121).

Almost surely, 2^81175205329 is an apocalyptic number.

It is an amenable number.

81175205329 is a deficient number, since it is larger than the sum of its proper divisors (14155155).

81175205329 is a wasteful number, since it uses less digits than its factorization.

81175205329 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14155154.

The product of its (nonzero) digits is 151200, while the sum is 43.

The spelling of 81175205329 in words is "eighty-one billion, one hundred seventy-five million, two hundred five thousand, three hundred twenty-nine".