3990221 has 4 divisors (see below), whose sum is σ = 4009344. Its totient is φ = 3971100.

The previous prime is 3990187. The next prime is 3990241. The reversal of 3990221 is 1220993.

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 3990221 - 2⁶ = 3990157 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3990241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9245 + ... + 9666.

It is an arithmetic number, because the mean of its divisors is an integer number (1002336).

Almost surely, 2^3990221 is an apocalyptic number.

It is an amenable number.

3990221 is a deficient number, since it is larger than the sum of its proper divisors (19123).

3990221 is a wasteful number, since it uses less digits than its factorization.

3990221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19122.

The product of its (nonzero) digits is 972, while the sum is 26.

The square root of 3990221 is about 1997.5537539701. The cubic root of 3990221 is about 158.6106396784.

The spelling of 3990221 in words is "three million, nine hundred ninety thousand, two hundred twenty-one".