5821 has 2 divisors, whose sum is σ = 5822.
Its totient is φ = 5820.
The previous prime is 5813. The next prime is 5827. The reversal of 5821 is 1285.
It is a happy number.
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 5625 + 196 = 75^2 + 14^2
It is a cyclic number.
It is not a de Polignac number, because 5821 - 23 = 5813 is a prime.
It is a plaindrome in base 16.
It is a junction number, because it is equal to n+sod(n) for n = 5795 and 5804.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (5827) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2910 + 2911.
It is an arithmetic number, because the mean of its divisors is an integer number (2911).
25821 is an apocalyptic number.
It is an amenable number.
5821 is a deficient number, since it is larger than the sum of its proper divisors (1).
5821 is an equidigital number, since it uses as much as digits as its factorization.
5821 is an odious number, because the sum of its binary digits is odd.
The product of its digits is 80, while the sum is 16.
The square root of 5821 is about 76.2954782408.
The cubic root of 5821 is about 17.9886760050.
The spelling of 5821 in words is "five thousand, eight hundred twenty-one".