565721 has 4 divisors (see below), whose sum is σ = 609252. Its totient is φ = 522192.

The previous prime is 565667. The next prime is 565723. The reversal of 565721 is 127565.

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

It can be written as a sum of positive squares in 2 ways, for example, as 24025 + 541696 = 155^2 + 736^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-565721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (565723) 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, 21746 + ... + 21771.

It is an arithmetic number, because the mean of its divisors is an integer number (152313).

2⁵⁶⁵⁷²¹ is an apocalyptic number.

It is an amenable number.

565721 is a deficient number, since it is larger than the sum of its proper divisors (43531).

565721 is a wasteful number, since it uses less digits than its factorization.

565721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43530.

The product of its digits is 2100, while the sum is 26.

The square root of 565721 is about 752.1442680763. The cubic root of 565721 is about 82.7054445050.

The spelling of 565721 in words is "five hundred sixty-five thousand, seven hundred twenty-one".