666665205 has 16 divisors (see below), whose sum is σ = 1067955840. Its totient is φ = 355124288.

The previous prime is 666665191. The next prime is 666665227. The reversal of 666665205 is 502566666.

It is a cyclic number.

It is not a de Polignac number, because 666665205 - 2¹² = 666661109 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13902 + ... + 39071.

It is an arithmetic number, because the mean of its divisors is an integer number (66747240).

Almost surely, 2^666665205 is an apocalyptic number.

It is an amenable number.

666665205 is a deficient number, since it is larger than the sum of its proper divisors (401290635).

666665205 is a wasteful number, since it uses less digits than its factorization.

666665205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53820.

The product of its (nonzero) digits is 388800, while the sum is 42.

The square root of 666665205 is about 25819.8606696473. The cubic root of 666665205 is about 873.5798262941.

The spelling of 666665205 in words is "six hundred sixty-six million, six hundred sixty-five thousand, two hundred five".