565215661 has 2 divisors, whose sum is σ = 565215662. Its totient is φ = 565215660.

The previous prime is 565215619. The next prime is 565215683. The reversal of 565215661 is 166512565.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 480924900 + 84290761 = 21930^2 + 9181^2 .

It is a cyclic number.

It is not a de Polignac number, because 565215661 - 2¹¹ = 565213613 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 565215661.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (565215611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 282607830 + 282607831.

It is an arithmetic number, because the mean of its divisors is an integer number (282607831).

Almost surely, 2^565215661 is an apocalyptic number.

It is an amenable number.

565215661 is a deficient number, since it is larger than the sum of its proper divisors (1).

565215661 is an equidigital number, since it uses as much as digits as its factorization.

565215661 is an evil number, because the sum of its binary digits is even.

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

The square root of 565215661 is about 23774.2646784291. The cubic root of 565215661 is about 826.8081119795.

The spelling of 565215661 in words is "five hundred sixty-five million, two hundred fifteen thousand, six hundred sixty-one".