3665221 has 4 divisors (see below), whose sum is σ = 4188832. Its totient is φ = 3141612.

The previous prime is 3665203. The next prime is 3665227. The reversal of 3665221 is 1225663.

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 a cyclic number.

It is not a de Polignac number, because 3665221 - 2⁹ = 3664709 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3665227) 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, 261795 + ... + 261808.

It is an arithmetic number, because the mean of its divisors is an integer number (1047208).

Almost surely, 2^3665221 is an apocalyptic number.

It is an amenable number.

3665221 is a deficient number, since it is larger than the sum of its proper divisors (523611).

3665221 is an equidigital number, since it uses as much as digits as its factorization.

3665221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 523610.

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

The square root of 3665221 is about 1914.4766909002. The cubic root of 3665221 is about 154.1818984058.

The spelling of 3665221 in words is "three million, six hundred sixty-five thousand, two hundred twenty-one".