28621 has 2 divisors, whose sum is σ = 28622.
Its totient is φ = 28620.
The previous prime is 28619. The next prime is 28627. The reversal of 28621 is 12682.
It is a happy number.
It is a weak prime.
It can be written as a sum of positive squares in only one way, i.e., 15625 + 12996 = 125^2 + 114^2
It is a cyclic number.
It is not a de Polignac number, because 28621 - 21 = 28619 is a prime.
Together with 28619, it forms a pair of twin primes.
It is a nialpdrome in base 15.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (28627) 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 as a sum of consecutive naturals, namely, 14310 + 14311.
It is an arithmetic number, because the mean of its divisors is an integer number (14311).
228621 is an apocalyptic number.
It is an amenable number.
28621 is a deficient number, since it is larger than the sum of its proper divisors (1).
28621 is an equidigital number, since it uses as much as digits as its factorization.
28621 is an odious number, because the sum of its binary digits is odd.
The product of its digits is 192, while the sum is 19.
The square root of 28621 is about 169.1774216614.
The cubic root of 28621 is about 30.5887409274.
It can be divided in two parts, 286 and 21, that multiplied together give a palindrome (6006).
The spelling of 28621 in words is "twenty-eight thousand, six hundred twenty-one".