1211000221 has 2 divisors, whose sum is σ = 1211000222. Its totient is φ = 1211000220.

The previous prime is 1211000159. The next prime is 1211000237. The reversal of 1211000221 is 1220001121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 784784196 + 426216025 = 28014^2 + 20645^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211000221 - 2¹⁹ = 1210475933 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1211000198 and 1211000207.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1211000291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605500110 + 605500111.

It is an arithmetic number, because the mean of its divisors is an integer number (605500111).

Almost surely, 2^1211000221 is an apocalyptic number.

It is an amenable number.

1211000221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211000221 is an equidigital number, since it uses as much as digits as its factorization.

1211000221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8, while the sum is 10.

The square root of 1211000221 is about 34799.4284579503. The cubic root of 1211000221 is about 1065.8957751097.

Adding to 1211000221 its reverse (1220001121), we get a palindrome (2431001342).

The spelling of 1211000221 in words is "one billion, two hundred eleven million, two hundred twenty-one", and thus it is an aban number.