81729655500 has 192 divisors, whose sum is σ = 247567896576. Its totient is φ = 20928960000.

The previous prime is 81729655499. The next prime is 81729655543. The reversal of 81729655500 is 555692718.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 81729655500.

It is an unprimeable number.

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 63 ways as a sum of consecutive naturals, for example, 6084792 + ... + 6098208.

It is an arithmetic number, because the mean of its divisors is an integer number (1289416128).

Almost surely, 2^81729655500 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81729655500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (123783948288).

81729655500 is an abundant number, since it is smaller than the sum of its proper divisors (165838241076).

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

81729655500 is a wasteful number, since it uses less digits than its factorization.

81729655500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13601 (or 13589 counting only the distinct ones).

The product of its (nonzero) digits is 756000, while the sum is 48.

The spelling of 81729655500 in words is "eighty-one billion, seven hundred twenty-nine million, six hundred fifty-five thousand, five hundred".