81547956872 has 32 divisors (see below), whose sum is σ = 156190152000. Its totient is φ = 39903969600.

The previous prime is 81547956871. The next prime is 81547956881. The reversal of 81547956872 is 27865974518.

It is not an unprimeable number, because it can be changed into a prime (81547956871) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 322754 + ... + 516977.

It is an arithmetic number, because the mean of its divisors is an integer number (4880942250).

Almost surely, 2^81547956872 is an apocalyptic number.

It is an amenable number.

81547956872 is a deficient number, since it is larger than the sum of its proper divisors (74642195128).

81547956872 is a wasteful number, since it uses less digits than its factorization.

81547956872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 839997 (or 839993 counting only the distinct ones).

The product of its digits is 33868800, while the sum is 62.

The spelling of 81547956872 in words is "eighty-one billion, five hundred forty-seven million, nine hundred fifty-six thousand, eight hundred seventy-two".