3640221 has 20 divisors (see below), whose sum is σ = 5857852. Its totient is φ = 2239488.

The previous prime is 3640207. The next prime is 3640223. The reversal of 3640221 is 1220463.

It is a happy number.

3640221 is a `hidden beast` number, since 3 + 640 + 2 + 21 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 236196 + 3404025 = 486^2 + 1845^2 .

It is not a de Polignac number, because 3640221 - 2¹⁰ = 3639197 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 3640194 and 3640203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3640223) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 676 + ... + 2781.

Almost surely, 2^3640221 is an apocalyptic number.

It is an amenable number.

3640221 is a deficient number, since it is larger than the sum of its proper divisors (2217631).

3640221 is a wasteful number, since it uses less digits than its factorization.

3640221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3482 (or 3473 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 3640221 is about 1907.9363196920. The cubic root of 3640221 is about 153.8305467309.

Adding to 3640221 its reverse (1220463), we get a palindrome (4860684).

The spelling of 3640221 in words is "three million, six hundred forty thousand, two hundred twenty-one".