81729618480 has 240 divisors, whose sum is σ = 280040379840. Its totient is φ = 21357084672.

The previous prime is 81729618457. The next prime is 81729618521. The reversal of 81729618480 is 8481692718.

81729618480 is a `hidden beast` number, since 8 + 1 + 72 + 96 + 1 + 8 + 480 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 7235397 + ... + 7246683.

It is an arithmetic number, because the mean of its divisors is an integer number (1166834916).

Almost surely, 2^81729618480 is an apocalyptic number.

81729618480 is a gapful number since it is divisible by the number (80) 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 81729618480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140020189920).

81729618480 is an abundant number, since it is smaller than the sum of its proper divisors (198310761360).

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

81729618480 is a wasteful number, since it uses less digits than its factorization.

81729618480 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11508 (or 11499 counting only the distinct ones).

The product of its (nonzero) digits is 1548288, while the sum is 54.

The spelling of 81729618480 in words is "eighty-one billion, seven hundred twenty-nine million, six hundred eighteen thousand, four hundred eighty".