565661 has 2 divisors, whose sum is σ = 565662. Its totient is φ = 565660.

The previous prime is 565651. The next prime is 565667. The reversal of 565661 is 166565.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 532900 + 32761 = 730^2 + 181^2 .

It is a cyclic number.

It is not a de Polignac number, because 565661 - 2⁶ = 565597 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (565667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 282830 + 282831.

It is an arithmetic number, because the mean of its divisors is an integer number (282831).

2⁵⁶⁵⁶⁶¹ is an apocalyptic number.

It is an amenable number.

565661 is a deficient number, since it is larger than the sum of its proper divisors (1).

565661 is an equidigital number, since it uses as much as digits as its factorization.

565661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5400, while the sum is 29.

The square root of 565661 is about 752.1043810536. The cubic root of 565661 is about 82.7025205065.

The spelling of 565661 in words is "five hundred sixty-five thousand, six hundred sixty-one".