81444563 has 4 divisors (see below), whose sum is σ = 81486288. Its totient is φ = 81402840.

The previous prime is 81444553. The next prime is 81444589. The reversal of 81444563 is 36544418.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81444563 - 2⁴ = 81444547 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81444553) 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 3 ways as a sum of consecutive naturals, for example, 17783 + ... + 21888.

It is an arithmetic number, because the mean of its divisors is an integer number (20371572).

Almost surely, 2^81444563 is an apocalyptic number.

81444563 is a deficient number, since it is larger than the sum of its proper divisors (41725).

81444563 is a wasteful number, since it uses less digits than its factorization.

81444563 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41724.

The product of its digits is 46080, while the sum is 35.

The square root of 81444563 is about 9024.6641488756. The cubic root of 81444563 is about 433.4649962180.

The spelling of 81444563 in words is "eighty-one million, four hundred forty-four thousand, five hundred sixty-three".