5721 has 4 divisors (see below), whose sum is σ = 7632.
Its totient is φ = 3812.
The previous prime is 5717. The next prime is 5737. The reversal of 5721 is 1275.
Adding to 5721 its reverse (1275), we get a palindrome (6996).
It can be divided in two parts, 57 and 21, that added together give a triangular number (78 = T12).
It is a happy number.
5721 is nontrivially palindromic in base 8.
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.
It is a cyclic number.
It is not a de Polignac number, because 5721 - 22 = 5717 is a prime.
It is a D-number.
5721 is an undulating number in base 8.
It is a Curzon number.
It is a plaindrome in base 12.
It is a nialpdrome in base 11.
It is a self number, because there is not a number n which added to its sum of digits gives 5721.
It is not an unprimeable number, because it can be changed into a prime (5701) 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, 951 + ... + 956.
It is an arithmetic number, because the mean of its divisors is an integer number (1908).
It is an amenable number.
5721 is a deficient number, since it is larger than the sum of its proper divisors (1911).
5721 is a wasteful number, since it uses less digits than its factorization.
5721 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 1910.
The product of its digits is 70, while the sum is 15.
The square root of 5721 is about 75.6372923894.
The cubic root of 5721 is about 17.8850702055.
The spelling of 5721 in words is "five thousand, seven hundred twenty-one".