665288705 has 20 divisors (see below), whose sum is σ = 843524052. Its totient is φ = 503724960.

The previous prime is 665288683. The next prime is 665288707. The reversal of 665288705 is 507882566.

It can be written as a sum of positive squares in 2 ways, for example, as 312900721 + 352387984 = 17689^2 + 18772^2 .

It is not a de Polignac number, because 665288705 - 2¹⁰ = 665287681 is a prime.

It is a super-2 number, since 2×665288705² = 885218122001154050, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 665288705.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665288707) 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 19 ways as a sum of consecutive naturals, for example, 651095 + ... + 652115.

It is a Proth number, since it is equal to 20303 ⋅ 2¹⁵ + 1 and 20303 < 2¹⁵.

Almost surely, 2^665288705 is an apocalyptic number.

It is an amenable number.

665288705 is a deficient number, since it is larger than the sum of its proper divisors (178235347).

665288705 is an frugal number, since it uses more digits than its factorization.

665288705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1102 (or 1045 counting only the distinct ones).

The product of its (nonzero) digits is 806400, while the sum is 47.

The square root of 665288705 is about 25793.1910588822. The cubic root of 665288705 is about 872.9781693790.

The spelling of 665288705 in words is "six hundred sixty-five million, two hundred eighty-eight thousand, seven hundred five".