1211203112221 has 2 divisors, whose sum is σ = 1211203112222. Its totient is φ = 1211203112220.

The previous prime is 1211203112183. The next prime is 1211203112267. The reversal of 1211203112221 is 1222113021121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1053057706596 + 158145405625 = 1026186^2 + 397675^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211203112221 - 2¹⁵ = 1211203079453 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1211203112281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605601556110 + 605601556111.

It is an arithmetic number, because the mean of its divisors is an integer number (605601556111).

Almost surely, 2^{1211203112221} is an apocalyptic number.

It is an amenable number.

1211203112221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211203112221 is an equidigital number, since it uses as much as digits as its factorization.

1211203112221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96, while the sum is 19.

Adding to 1211203112221 its reverse (1222113021121), we get a palindrome (2433316133342).

The spelling of 1211203112221 in words is "one trillion, two hundred eleven billion, two hundred three million, one hundred twelve thousand, two hundred twenty-one".