1211000221009 has 2 divisors, whose sum is σ = 1211000221010. Its totient is φ = 1211000221008.

The previous prime is 1211000220949. The next prime is 1211000221021. The reversal of 1211000221009 is 9001220001121.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1207464729409 + 3535491600 = 1098847^2 + 59460^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211000221009 - 2²⁵ = 1210966666577 is a prime.

It is not a weakly prime, because it can be changed into another prime (1211000224009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605500110504 + 605500110505.

It is an arithmetic number, because the mean of its divisors is an integer number (605500110505).

Almost surely, 2^{1211000221009} is an apocalyptic number.

It is an amenable number.

1211000221009 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211000221009 is an equidigital number, since it uses as much as digits as its factorization.

1211000221009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 19.

The spelling of 1211000221009 in words is "one trillion, two hundred eleven billion, two hundred twenty-one thousand, nine".