665289 has 12 divisors (see below), whose sum is σ = 994500. Its totient is φ = 428064.

The previous prime is 665279. The next prime is 665293. The reversal of 665289 is 982566.

It can be written as a sum of positive squares in 2 ways, for example, as 501264 + 164025 = 708^2 + 405^2 .

It is not a de Polignac number, because 665289 - 2⁹ = 664777 is a prime.

665289 is a lucky number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 665289.

It is not an unprimeable number, because it can be changed into a prime (665239) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1014 + ... + 1535.

It is an arithmetic number, because the mean of its divisors is an integer number (82875).

2⁶⁶⁵²⁸⁹ is an apocalyptic number.

It is an amenable number.

665289 is a deficient number, since it is larger than the sum of its proper divisors (329211).

665289 is a wasteful number, since it uses less digits than its factorization.

665289 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2584 (or 2581 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 665289 is about 815.6524995364. The cubic root of 665289 is about 87.2978298410.

The spelling of 665289 in words is "six hundred sixty-five thousand, two hundred eighty-nine".