81617176812729 has 4 divisors (see below), whose sum is σ = 108822902416976. Its totient is φ = 54411451208484.

The previous prime is 81617176812727. The next prime is 81617176812751. The reversal of 81617176812729 is 92721867171618.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 81617176812729 - 2¹ = 81617176812727 is a prime.

It is a super-2 number, since 2×81617176812729² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81617176812729.

It is not an unprimeable number, because it can be changed into a prime (81617176812727) 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, 13602862802119 + ... + 13602862802124.

It is an arithmetic number, because the mean of its divisors is an integer number (27205725604244).

Almost surely, 2^{81617176812729} is an apocalyptic number.

It is an amenable number.

81617176812729 is a deficient number, since it is larger than the sum of its proper divisors (27205725604247).

81617176812729 is a wasteful number, since it uses less digits than its factorization.

81617176812729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27205725604246.

The product of its digits is 28449792, while the sum is 66.

The spelling of 81617176812729 in words is "eighty-one trillion, six hundred seventeen billion, one hundred seventy-six million, eight hundred twelve thousand, seven hundred twenty-nine".