81729341904 has 320 divisors, whose sum is σ = 260874731520. Its totient is φ = 21535303680.

The previous prime is 81729341879. The next prime is 81729341923. The reversal of 81729341904 is 40914392718.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 93191514 + ... + 93192390.

It is an arithmetic number, because the mean of its divisors is an integer number (815233536).

Almost surely, 2^81729341904 is an apocalyptic number.

81729341904 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81729341904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (130437365760).

81729341904 is an abundant number, since it is smaller than the sum of its proper divisors (179145389616).

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

81729341904 is a wasteful number, since it uses less digits than its factorization.

81729341904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1338 (or 1332 counting only the distinct ones).

The product of its (nonzero) digits is 435456, while the sum is 48.

The spelling of 81729341904 in words is "eighty-one billion, seven hundred twenty-nine million, three hundred forty-one thousand, nine hundred four".