565861 has 4 divisors (see below), whose sum is σ = 567424. Its totient is φ = 564300.

The previous prime is 565849. The next prime is 565867. The reversal of 565861 is 168565.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 168565 = 5 ⋅33713.

It is a cyclic number.

It is not a de Polignac number, because 565861 - 2¹¹ = 563813 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (565867) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 76 + ... + 1066.

It is an arithmetic number, because the mean of its divisors is an integer number (141856).

2⁵⁶⁵⁸⁶¹ is an apocalyptic number.

It is an amenable number.

565861 is a deficient number, since it is larger than the sum of its proper divisors (1563).

565861 is an equidigital number, since it uses as much as digits as its factorization.

565861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1562.

The product of its digits is 7200, while the sum is 31.

The square root of 565861 is about 752.2373295709. The cubic root of 565861 is about 82.7122663643.

The spelling of 565861 in words is "five hundred sixty-five thousand, eight hundred sixty-one".