3965221 has 4 divisors (see below), whose sum is σ = 4270252. Its totient is φ = 3660192.

The previous prime is 3965219. The next prime is 3965231. The reversal of 3965221 is 1225693.

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 396900 + 3568321 = 630^2 + 1889^2 .

It is a cyclic number.

It is not a de Polignac number, because 3965221 - 2¹ = 3965219 is a prime.

It is a Duffinian number.

3965221 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 3965221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3965231) 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, 152496 + ... + 152521.

It is an arithmetic number, because the mean of its divisors is an integer number (1067563).

Almost surely, 2^3965221 is an apocalyptic number.

It is an amenable number.

3965221 is a deficient number, since it is larger than the sum of its proper divisors (305031).

3965221 is a wasteful number, since it uses less digits than its factorization.

3965221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 305030.

The product of its digits is 3240, while the sum is 28.

The square root of 3965221 is about 1991.2862677174. The cubic root of 3965221 is about 158.2786968150.

It can be divided in two parts, 3965 and 221, that added together give a triangular number (4186 = T₉₁).

The spelling of 3965221 in words is "three million, nine hundred sixty-five thousand, two hundred twenty-one".