81571573888 has 32 divisors (see below), whose sum is σ = 185720996160. Its totient is φ = 34959245568.

The previous prime is 81571573777. The next prime is 81571573931. The reversal of 81571573888 is 88837517518.

It is a tau number, because it is divible by the number of its divisors (32).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45518956 + ... + 45520747.

It is an arithmetic number, because the mean of its divisors is an integer number (5803781130).

Almost surely, 2^81571573888 is an apocalyptic number.

It is an amenable number.

81571573888 is an abundant number, since it is smaller than the sum of its proper divisors (104149422272).

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

81571573888 is an equidigital number, since it uses as much as digits as its factorization.

81571573888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91039724 (or 91039712 counting only the distinct ones).

The product of its digits is 15052800, while the sum is 61.

The spelling of 81571573888 in words is "eighty-one billion, five hundred seventy-one million, five hundred seventy-three thousand, eight hundred eighty-eight".