665712205 has 4 divisors (see below), whose sum is σ = 798854652. Its totient is φ = 532569760.

The previous prime is 665712199. The next prime is 665712211. The reversal of 665712205 is 502217566.

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

It is an interprime number because it is at equal distance from previous prime (665712199) and next prime (665712211).

It can be written as a sum of positive squares in 2 ways, for example, as 80604484 + 585107721 = 8978^2 + 24189^2 .

It is not a de Polignac number, because 665712205 - 2⁷ = 665712077 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66571216 + ... + 66571225.

It is an arithmetic number, because the mean of its divisors is an integer number (199713663).

Almost surely, 2^665712205 is an apocalyptic number.

It is an amenable number.

665712205 is a deficient number, since it is larger than the sum of its proper divisors (133142447).

665712205 is a wasteful number, since it uses less digits than its factorization.

665712205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133142446.

The product of its (nonzero) digits is 25200, while the sum is 34.

The square root of 665712205 is about 25801.3992837598. The cubic root of 665712205 is about 873.1633660874.

The spelling of 665712205 in words is "six hundred sixty-five million, seven hundred twelve thousand, two hundred five".