81729266099670 has 192 divisors, whose sum is σ = 245037438696960. Its totient is φ = 18512964578304.

The previous prime is 81729266099653. The next prime is 81729266099671. The reversal of 81729266099670 is 7699066292718.

81729266099670 is a `hidden beast` number, since 8 + 1 + 7 + 2 + 9 + 2 + 6 + 609 + 9 + 6 + 7 + 0 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81729266099671) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 511562661 + ... + 511722399.

It is an arithmetic number, because the mean of its divisors is an integer number (1276236659880).

Almost surely, 2^{81729266099670} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81729266099670, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (122518719348480).

81729266099670 is an abundant number, since it is smaller than the sum of its proper divisors (163308172597290).

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

81729266099670 is a wasteful number, since it uses less digits than its factorization.

81729266099670 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 167059 (or 167056 counting only the distinct ones).

The product of its (nonzero) digits is 246903552, while the sum is 72.

The spelling of 81729266099670 in words is "eighty-one trillion, seven hundred twenty-nine billion, two hundred sixty-six million, ninety-nine thousand, six hundred seventy".