1211222120221 has 16 divisors (see below), whose sum is σ = 1283500617840. Its totient is φ = 1139058524160.

The previous prime is 1211222120209. The next prime is 1211222120243. The reversal of 1211222120221 is 1220212221121.

It can be written as a sum of positive squares in 8 ways, for example, as 168752532025 + 1042469588196 = 410795^2 + 1021014^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211222120221 - 2⁷ = 1211222120093 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211222190221) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 165441241 + ... + 165448561.

It is an arithmetic number, because the mean of its divisors is an integer number (80218788615).

Almost surely, 2^{1211222120221} is an apocalyptic number.

It is an amenable number.

1211222120221 is a deficient number, since it is larger than the sum of its proper divisors (72278497619).

1211222120221 is a wasteful number, since it uses less digits than its factorization.

1211222120221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13824.

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 1211222120221 its reverse (1220212221121), we get a palindrome (2431434341342).

The spelling of 1211222120221 in words is "one trillion, two hundred eleven billion, two hundred twenty-two million, one hundred twenty thousand, two hundred twenty-one".