28042561 has 2 divisors, whose sum is σ = 28042562. Its totient is φ = 28042560.

The previous prime is 28042541. The next prime is 28042577. The reversal of 28042561 is 16524082.

28042561 = 3744² + 3745².

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14025025 + 14017536 = 3745^2 + 3744^2 .

It is a cyclic number.

It is not a de Polignac number, because 28042561 - 2⁵ = 28042529 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (28042501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14021280 + 14021281.

It is an arithmetic number, because the mean of its divisors is an integer number (14021281).

Almost surely, 2^28042561 is an apocalyptic number.

28042561 is the 3745-th centered square number.

It is an amenable number.

28042561 is a deficient number, since it is larger than the sum of its proper divisors (1).

28042561 is an equidigital number, since it uses as much as digits as its factorization.

28042561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3840, while the sum is 28.

The square root of 28042561 is about 5295.5227315157. The cubic root of 28042561 is about 303.8126767533.

The spelling of 28042561 in words is "twenty-eight million, forty-two thousand, five hundred sixty-one".