81338384577 has 24 divisors (see below), whose sum is σ = 111216021600. Its totient is φ = 52876732608.

The previous prime is 81338384563. The next prime is 81338384581. The reversal of 81338384577 is 77548383318.

It is not a de Polignac number, because 81338384577 - 2²³ = 81329995969 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81338384177) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3421749 + ... + 3445437.

It is an arithmetic number, because the mean of its divisors is an integer number (4634000900).

Almost surely, 2^81338384577 is an apocalyptic number.

It is an amenable number.

81338384577 is a deficient number, since it is larger than the sum of its proper divisors (29877637023).

81338384577 is a wasteful number, since it uses less digits than its factorization.

81338384577 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24397 (or 24354 counting only the distinct ones).

The product of its digits is 13547520, while the sum is 57.

The spelling of 81338384577 in words is "eighty-one billion, three hundred thirty-eight million, three hundred eighty-four thousand, five hundred seventy-seven".