28568821 has 2 divisors, whose sum is σ = 28568822. Its totient is φ = 28568820.

The previous prime is 28568807. The next prime is 28568831. The reversal of 28568821 is 12886582.

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., 23415921 + 5152900 = 4839^2 + 2270^2 .

It is a cyclic number.

It is not a de Polignac number, because 28568821 - 2⁷ = 28568693 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28568831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14284410 + 14284411.

It is an arithmetic number, because the mean of its divisors is an integer number (14284411).

Almost surely, 2^28568821 is an apocalyptic number.

It is an amenable number.

28568821 is a deficient number, since it is larger than the sum of its proper divisors (1).

28568821 is an equidigital number, since it uses as much as digits as its factorization.

28568821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 61440, while the sum is 40.

The square root of 28568821 is about 5344.9809167106. The cubic root of 28568821 is about 305.7014082207.

The spelling of 28568821 in words is "twenty-eight million, five hundred sixty-eight thousand, eight hundred twenty-one".