561566521 has 2 divisors, whose sum is σ = 561566522. Its totient is φ = 561566520.

The previous prime is 561566507. The next prime is 561566531. The reversal of 561566521 is 125665165.

561566521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 301196025 + 260370496 = 17355^2 + 16136^2 .

It is a cyclic number.

It is not a de Polignac number, because 561566521 - 2⁷ = 561566393 is a prime.

It is not a weakly prime, because it can be changed into another prime (561566531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 280783260 + 280783261.

It is an arithmetic number, because the mean of its divisors is an integer number (280783261).

Almost surely, 2^561566521 is an apocalyptic number.

It is an amenable number.

561566521 is a deficient number, since it is larger than the sum of its proper divisors (1).

561566521 is an equidigital number, since it uses as much as digits as its factorization.

561566521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 54000, while the sum is 37.

The square root of 561566521 is about 23697.3948146204. The cubic root of 561566521 is about 825.0249253565.

The spelling of 561566521 in words is "five hundred sixty-one million, five hundred sixty-six thousand, five hundred twenty-one".