565921 has 2 divisors, whose sum is σ = 565922. Its totient is φ = 565920.

The previous prime is 565919. The next prime is 565937. The reversal of 565921 is 129565.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 435600 + 130321 = 660^2 + 361^2 .

It is a cyclic number.

It is not a de Polignac number, because 565921 - 2¹ = 565919 is a prime.

Together with 565919, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 565921.

It is not a weakly prime, because it can be changed into another prime (568921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 282960 + 282961.

It is an arithmetic number, because the mean of its divisors is an integer number (282961).

2⁵⁶⁵⁹²¹ is an apocalyptic number.

It is an amenable number.

565921 is a deficient number, since it is larger than the sum of its proper divisors (1).

565921 is an equidigital number, since it uses as much as digits as its factorization.

565921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2700, while the sum is 28.

The square root of 565921 is about 752.2772095445. The cubic root of 565921 is about 82.7151896738.

The spelling of 565921 in words is "five hundred sixty-five thousand, nine hundred twenty-one".