505665 has 24 divisors (see below), whose sum is σ = 929448. Its totient is φ = 253440.

The previous prime is 505663. The next prime is 505669. The reversal of 505665 is 566505.

It can be written as a sum of positive squares in 4 ways, for example, as 173889 + 331776 = 417^2 + 576^2 .

It is not a de Polignac number, because 505665 - 2¹ = 505663 is a prime.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 505665.

It is not an unprimeable number, because it can be changed into a prime (505663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 435 + ... + 1095.

It is an arithmetic number, because the mean of its divisors is an integer number (38727).

2⁵⁰⁵⁶⁶⁵ is an apocalyptic number.

It is an amenable number.

505665 is a deficient number, since it is larger than the sum of its proper divisors (423783).

505665 is a wasteful number, since it uses less digits than its factorization.

505665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 689 (or 686 counting only the distinct ones).

The product of its (nonzero) digits is 4500, while the sum is 27.

The square root of 505665 is about 711.1012586123. The cubic root of 505665 is about 79.6686818310.

The spelling of 505665 in words is "five hundred five thousand, six hundred sixty-five".