81175205328 has 80 divisors (see below), whose sum is σ = 240060825600. Its totient is φ = 23154139008.

The previous prime is 81175205317. The next prime is 81175205359. The reversal of 81175205328 is 82350257118.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a self number, because there is not a number n which added to its sum of digits gives 81175205328.

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 400 + ... + 402927.

It is an arithmetic number, because the mean of its divisors is an integer number (3000760320).

Almost surely, 2^81175205328 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 81175205328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (120030412800).

81175205328 is an abundant number, since it is smaller than the sum of its proper divisors (158885620272).

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

81175205328 is a wasteful number, since it uses less digits than its factorization.

81175205328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 403944 (or 403938 counting only the distinct ones).

The product of its (nonzero) digits is 134400, while the sum is 42.

The spelling of 81175205328 in words is "eighty-one billion, one hundred seventy-five million, two hundred five thousand, three hundred twenty-eight".