1990221 has 4 divisors (see below), whose sum is σ = 2653632. Its totient is φ = 1326812.

The previous prime is 1990211. The next prime is 1990223. The reversal of 1990221 is 1220991.

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 1990221 - 2⁵ = 1990189 is a prime.

It is a D-number.

It is a junction number, because it is equal to n+sod(n) for n = 1990191 and 1990200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1990223) 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, 331701 + ... + 331706.

It is an arithmetic number, because the mean of its divisors is an integer number (663408).

2^1990221 is an apocalyptic number.

It is an amenable number.

1990221 is a deficient number, since it is larger than the sum of its proper divisors (663411).

1990221 is an equidigital number, since it uses as much as digits as its factorization.

1990221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 663410.

The product of its (nonzero) digits is 324, while the sum is 24.

The square root of 1990221 is about 1410.7519271651. The cubic root of 1990221 is about 125.7864232650.

It can be divided in two parts, 1990 and 221, that added together give a triangular number (2211 = T₆₆).

The spelling of 1990221 in words is "one million, nine hundred ninety thousand, two hundred twenty-one".