81729105696 has 144 divisors (see below), whose sum is σ = 274779086400. Its totient is φ = 22545944064.

The previous prime is 81729105691. The next prime is 81729105697. The reversal of 81729105696 is 69650192718.

81729105696 is a `hidden beast` number, since 8 + 1 + 72 + 9 + 1 + 0 + 569 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is not an unprimeable number, because it can be changed into a prime (81729105691) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 640506 + ... + 757433.

It is an arithmetic number, because the mean of its divisors is an integer number (1908188100).

Almost surely, 2^81729105696 is an apocalyptic number.

It is an amenable number.

81729105696 is an abundant number, since it is smaller than the sum of its proper divisors (193049980704).

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

81729105696 is a wasteful number, since it uses less digits than its factorization.

81729105696 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1397991 (or 1397980 counting only the distinct ones).

The product of its (nonzero) digits is 1632960, while the sum is 54.

The spelling of 81729105696 in words is "eighty-one billion, seven hundred twenty-nine million, one hundred five thousand, six hundred ninety-six".