81389397444 has 24 divisors (see below), whose sum is σ = 189924231168. Its totient is φ = 27127565280.

The previous prime is 81389397413. The next prime is 81389397449. The reversal of 81389397444 is 44479398318.

It is not an unprimeable number, because it can be changed into a prime (81389397449) 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, 123972 + ... + 422075.

It is an arithmetic number, because the mean of its divisors is an integer number (7913509632).

Almost surely, 2^81389397444 is an apocalyptic number.

It is an amenable number.

81389397444 is an abundant number, since it is smaller than the sum of its proper divisors (108534833724).

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

81389397444 is a wasteful number, since it uses less digits than its factorization.

81389397444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 558475 (or 558473 counting only the distinct ones).

The product of its digits is 20901888, while the sum is 60.

The spelling of 81389397444 in words is "eighty-one billion, three hundred eighty-nine million, three hundred ninety-seven thousand, four hundred forty-four".