81564508803 has 16 divisors (see below), whose sum is σ = 109788359040. Its totient is φ = 53858678016.

The previous prime is 81564508741. The next prime is 81564508819. The reversal of 81564508803 is 30880546518.

It is not a de Polignac number, because 81564508803 - 2²⁰ = 81563460227 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81564508873) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2128176 + ... + 2166162.

It is an arithmetic number, because the mean of its divisors is an integer number (6861772440).

Almost surely, 2^81564508803 is an apocalyptic number.

81564508803 is a deficient number, since it is larger than the sum of its proper divisors (28223850237).

81564508803 is a wasteful number, since it uses less digits than its factorization.

81564508803 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44786.

The product of its (nonzero) digits is 921600, while the sum is 48.

The spelling of 81564508803 in words is "eighty-one billion, five hundred sixty-four million, five hundred eight thousand, eight hundred three".