1890221 has 2 divisors, whose sum is σ = 1890222. Its totient is φ = 1890220.

The previous prime is 1890211. The next prime is 1890227. The reversal of 1890221 is 1220981.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1297321 + 592900 = 1139^2 + 770^2 .

It is an emirp because it is prime and its reverse (1220981) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1890221 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1890227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 945110 + 945111.

It is an arithmetic number, because the mean of its divisors is an integer number (945111).

2^1890221 is an apocalyptic number.

It is an amenable number.

1890221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1890221 is an equidigital number, since it uses as much as digits as its factorization.

1890221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 1890221 is about 1374.8530830602. The cubic root of 1890221 is about 123.6433778755.

The spelling of 1890221 in words is "one million, eight hundred ninety thousand, two hundred twenty-one".