666205 has 4 divisors (see below), whose sum is σ = 799452. Its totient is φ = 532960.

The previous prime is 666203. The next prime is 666229. The reversal of 666205 is 502666.

666205 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 527076 + 139129 = 726^2 + 373^2 .

It is not a de Polignac number, because 666205 - 2¹ = 666203 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 666205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666203) 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, 66616 + ... + 66625.

It is an arithmetic number, because the mean of its divisors is an integer number (199863).

2⁶⁶⁶²⁰⁵ is an apocalyptic number.

It is an amenable number.

666205 is a deficient number, since it is larger than the sum of its proper divisors (133247).

666205 is a wasteful number, since it uses less digits than its factorization.

666205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133246.

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 666205 is about 816.2138200251. The cubic root of 666205 is about 87.3378766680.

The spelling of 666205 in words is "six hundred sixty-six thousand, two hundred five".