1211221110221 has 2 divisors, whose sum is σ = 1211221110222. Its totient is φ = 1211221110220.

The previous prime is 1211221110179. The next prime is 1211221110257. The reversal of 1211221110221 is 1220111221121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1180547440900 + 30673669321 = 1086530^2 + 175139^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211221110221 - 2⁶ = 1211221110157 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1211221110221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1211221116221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605610555110 + 605610555111.

It is an arithmetic number, because the mean of its divisors is an integer number (605610555111).

Almost surely, 2^{1211221110221} is an apocalyptic number.

It is an amenable number.

1211221110221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211221110221 is an equidigital number, since it uses as much as digits as its factorization.

1211221110221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 1211221110221 its reverse (1220111221121), we get a palindrome (2431332331342).

The spelling of 1211221110221 in words is "one trillion, two hundred eleven billion, two hundred twenty-one million, one hundred ten thousand, two hundred twenty-one".