565991 has 4 divisors (see below), whose sum is σ = 595800. Its totient is φ = 536184.

The previous prime is 565979. The next prime is 565997. The reversal of 565991 is 199565.

565991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 565991 - 2¹⁴ = 549607 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 (565997) 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, 14876 + ... + 14913.

It is an arithmetic number, because the mean of its divisors is an integer number (148950).

2⁵⁶⁵⁹⁹¹ is an apocalyptic number.

565991 is a deficient number, since it is larger than the sum of its proper divisors (29809).

565991 is a wasteful number, since it uses less digits than its factorization.

565991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29808.

The product of its digits is 12150, while the sum is 35.

The square root of 565991 is about 752.3237335084. The cubic root of 565991 is about 82.7185999405.

The spelling of 565991 in words is "five hundred sixty-five thousand, nine hundred ninety-one".