81571455812 has 36 divisors (see below), whose sum is σ = 181152198864. Its totient is φ = 31781085840.

The previous prime is 81571455781. The next prime is 81571455821. The reversal of 81571455812 is 21855417518.

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 11 ways as a sum of consecutive naturals, for example, 18915158 + ... + 18919469.

It is an arithmetic number, because the mean of its divisors is an integer number (5032005524).

Almost surely, 2^81571455812 is an apocalyptic number.

It is an amenable number.

81571455812 is an abundant number, since it is smaller than the sum of its proper divisors (99580743052).

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

81571455812 is a wasteful number, since it uses less digits than its factorization.

81571455812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37834656 (or 37834647 counting only the distinct ones).

The product of its digits is 448000, while the sum is 47.

The spelling of 81571455812 in words is "eighty-one billion, five hundred seventy-one million, four hundred fifty-five thousand, eight hundred twelve".