565537321561 has 2 divisors, whose sum is σ = 565537321562. Its totient is φ = 565537321560.

The previous prime is 565537321549. The next prime is 565537321571. The reversal of 565537321561 is 165123735565.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 537793422336 + 27743899225 = 733344^2 + 166565^2 .

It is a cyclic number.

It is not a de Polignac number, because 565537321561 - 2¹⁷ = 565537190489 is a prime.

It is not a weakly prime, because it can be changed into another prime (565537321511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 282768660780 + 282768660781.

It is an arithmetic number, because the mean of its divisors is an integer number (282768660781).

Almost surely, 2^565537321561 is an apocalyptic number.

It is an amenable number.

565537321561 is a deficient number, since it is larger than the sum of its proper divisors (1).

565537321561 is an equidigital number, since it uses as much as digits as its factorization.

565537321561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2835000, while the sum is 49.

The spelling of 565537321561 in words is "five hundred sixty-five billion, five hundred thirty-seven million, three hundred twenty-one thousand, five hundred sixty-one".