28000561 has 2 divisors, whose sum is σ = 28000562. Its totient is φ = 28000560.

The previous prime is 28000559. The next prime is 28000571. The reversal of 28000561 is 16500082.

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., 25310961 + 2689600 = 5031^2 + 1640^2 .

It is a cyclic number.

It is not a de Polignac number, because 28000561 - 2¹ = 28000559 is a prime.

Together with 28000559, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (28000541) 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, 14000280 + 14000281.

It is an arithmetic number, because the mean of its divisors is an integer number (14000281).

Almost surely, 2^28000561 is an apocalyptic number.

It is an amenable number.

28000561 is a deficient number, since it is larger than the sum of its proper divisors (1).

28000561 is an equidigital number, since it uses as much as digits as its factorization.

28000561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 28000561 is about 5291.5556313810. Note that the first 3 decimals coincide. The cubic root of 28000561 is about 303.6609251817.

It can be divided in two parts, 28000 and 561, that added together give a 4-th power (28561 = 13⁴).

The spelling of 28000561 in words is "twenty-eight million, five hundred sixty-one", and thus it is an aban number.