81729618173 has 8 divisors (see below), whose sum is σ = 93478318080. Its totient is φ = 69999178320.

The previous prime is 81729618167. The next prime is 81729618181. The reversal of 81729618173 is 37181692718.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81729618173 - 2⁸ = 81729617917 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81729618073) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4555418 + ... + 4573323.

It is an arithmetic number, because the mean of its divisors is an integer number (11684789760).

Almost surely, 2^81729618173 is an apocalyptic number.

It is an amenable number.

81729618173 is a deficient number, since it is larger than the sum of its proper divisors (11748699907).

81729618173 is a wasteful number, since it uses less digits than its factorization.

81729618173 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9130027.

The product of its digits is 1016064, while the sum is 53.

The spelling of 81729618173 in words is "eighty-one billion, seven hundred twenty-nine million, six hundred eighteen thousand, one hundred seventy-three".