81010005644 has 24 divisors (see below), whose sum is σ = 146646576720. Its totient is φ = 39126735936.

The previous prime is 81010005631. The next prime is 81010005647. The reversal of 81010005644 is 44650001018.

It is not an unprimeable number, because it can be changed into a prime (81010005647) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 1948367 + ... + 1989510.

It is an arithmetic number, because the mean of its divisors is an integer number (6110274030).

Almost surely, 2^81010005644 is an apocalyptic number.

It is an amenable number.

81010005644 is a deficient number, since it is larger than the sum of its proper divisors (65636571076).

81010005644 is a wasteful number, since it uses less digits than its factorization.

81010005644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3938057 (or 3938055 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 29.

The spelling of 81010005644 in words is "eighty-one billion, ten million, five thousand, six hundred forty-four".