3666209 has 4 divisors (see below), whose sum is σ = 3792660. Its totient is φ = 3539760.

The previous prime is 3666197. The next prime is 3666233. The reversal of 3666209 is 9026663.

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 2411809 + 1254400 = 1553^2 + 1120^2 .

It is a cyclic number.

It is not a de Polignac number, because 3666209 - 2²⁰ = 2617633 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (3666409) 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, 63182 + ... + 63239.

It is an arithmetic number, because the mean of its divisors is an integer number (948165).

Almost surely, 2^3666209 is an apocalyptic number.

It is an amenable number.

3666209 is a deficient number, since it is larger than the sum of its proper divisors (126451).

3666209 is a wasteful number, since it uses less digits than its factorization.

3666209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126450.

The product of its (nonzero) digits is 11664, while the sum is 32.

The square root of 3666209 is about 1914.7347074726. The cubic root of 3666209 is about 154.1957509611.

The spelling of 3666209 in words is "three million, six hundred sixty-six thousand, two hundred nine".