660565 has 4 divisors (see below), whose sum is σ = 792684. Its totient is φ = 528448.

The previous prime is 660563. The next prime is 660589. The reversal of 660565 is 565066.

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 178929 + 481636 = 423^2 + 694^2 .

It is a cyclic number.

It is not a de Polignac number, because 660565 - 2¹ = 660563 is a prime.

It is a super-2 number, since 2×660565² = 872692238450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660563) 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, 66052 + ... + 66061.

It is an arithmetic number, because the mean of its divisors is an integer number (198171).

2⁶⁶⁰⁵⁶⁵ is an apocalyptic number.

It is an amenable number.

660565 is a deficient number, since it is larger than the sum of its proper divisors (132119).

660565 is a wasteful number, since it uses less digits than its factorization.

660565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132118.

The product of its (nonzero) digits is 5400, while the sum is 28.

The square root of 660565 is about 812.7514995372. The cubic root of 660565 is about 87.0907143814.

It can be divided in two parts, 6605 and 65, that added together give a triangular number (6670 = T₁₁₅).

The spelling of 660565 in words is "six hundred sixty thousand, five hundred sixty-five".