5591 has 2 divisors, whose sum is σ = 5592.
Its totient is φ = 5590.
The previous prime is 5581. The next prime is 5623. The reversal of 5591 is 1955.
It is a weak prime.
It is a cyclic number.
It is not a de Polignac number, because 5591 - 26 = 5527 is a prime.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (5501) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2795 + 2796.
It is an arithmetic number, because the mean of its divisors is an integer number (2796).
25591 is an apocalyptic number.
5591 is a deficient number, since it is larger than the sum of its proper divisors (1).
5591 is an equidigital number, since it uses as much as digits as its factorization.
5591 is an odious number, because the sum of its binary digits is odd.
The product of its digits is 225, while the sum is 20.
The square root of 5591 is about 74.7729897757.
The cubic root of 5591 is about 17.7485616767.
It can be divided in two parts, 55 and 91, that multiplied together give a palindrome (5005).
The spelling of 5591 in words is "five thousand, five hundred ninety-one".