81440593 has 16 divisors (see below), whose sum is σ = 92915200. Its totient is φ = 71182800.

The previous prime is 81440573. The next prime is 81440617. The reversal of 81440593 is 39504418.

It is not a de Polignac number, because 81440593 - 2⁵ = 81440561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81440533) 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, 40768 + ... + 42718.

It is an arithmetic number, because the mean of its divisors is an integer number (5807200).

Almost surely, 2^81440593 is an apocalyptic number.

It is an amenable number.

81440593 is a deficient number, since it is larger than the sum of its proper divisors (11474607).

81440593 is a wasteful number, since it uses less digits than its factorization.

81440593 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2009 (or 1983 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 34.

The square root of 81440593 is about 9024.4441934116. Note that the first 3 decimals coincide. The cubic root of 81440593 is about 433.4579530468.

The spelling of 81440593 in words is "eighty-one million, four hundred forty thousand, five hundred ninety-three".