16591 has 4 divisors (see below), whose sum is σ = 16992. Its totient is φ = 16192.

The previous prime is 16573. The next prime is 16603. The reversal of 16591 is 19561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19561 = 31 ⋅631.

It is a cyclic number.

It is not a de Polignac number, because 16591 - 2¹¹ = 14543 is a prime.

It is a super-2 number, since 2×16591² = 550522562, which contains 22 as substring.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

16591 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 130 + ... + 223.

It is an arithmetic number, because the mean of its divisors is an integer number (4248).

2¹⁶⁵⁹¹ is an apocalyptic number.

16591 is a deficient number, since it is larger than the sum of its proper divisors (401).

16591 is an equidigital number, since it uses as much as digits as its factorization.

16591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 400.

The product of its digits is 270, while the sum is 22.

The square root of 16591 is about 128.8060557583. The cubic root of 16591 is about 25.5049330454.

Adding to 16591 its product of digits (270), we get a palindrome (16861).

It can be divided in two parts, 165 and 91, that added together give a 8-th power (256 = 2⁸).

The spelling of 16591 in words is "sixteen thousand, five hundred ninety-one".