81593 has 4 divisors (see below), whose sum is σ = 82320. Its totient is φ = 80868.

The previous prime is 81569. The next prime is 81611. The reversal of 81593 is 39518.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 39518 = 2 ⋅19759.

It is a cyclic number.

It is not a de Polignac number, because 81593 - 2¹⁶ = 16057 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81533) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 155 + ... + 432.

It is an arithmetic number, because the mean of its divisors is an integer number (20580).

2⁸¹⁵⁹³ is an apocalyptic number.

It is an amenable number.

81593 is a deficient number, since it is larger than the sum of its proper divisors (727).

81593 is a wasteful number, since it uses less digits than its factorization.

81593 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 726.

The product of its digits is 1080, while the sum is 26.

The square root of 81593 is about 285.6448844282. The cubic root of 81593 is about 43.3728173983.

The spelling of 81593 in words is "eighty-one thousand, five hundred ninety-three".