666201 has 4 divisors (see below), whose sum is σ = 888272. Its totient is φ = 444132.

The previous prime is 666191. The next prime is 666203. The reversal of 666201 is 102666.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 666201 - 2⁷ = 666073 is a prime.

It is a D-number.

It is a Duffinian 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, 111031 + ... + 111036.

It is an arithmetic number, because the mean of its divisors is an integer number (222068).

2⁶⁶⁶²⁰¹ is an apocalyptic number.

It is an amenable number.

666201 is a deficient number, since it is larger than the sum of its proper divisors (222071).

666201 is a wasteful number, since it uses less digits than its factorization.

666201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222070.

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 666201 is about 816.2113696831. The cubic root of 666201 is about 87.3377018708.

Adding to 666201 its reverse (102666), we get a palindrome (768867).

The spelling of 666201 in words is "six hundred sixty-six thousand, two hundred one".