1211122222021 has 2 divisors, whose sum is σ = 1211122222022. Its totient is φ = 1211122222020.

The previous prime is 1211122222019. The next prime is 1211122222027. The reversal of 1211122222021 is 1202222211121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1200898181025 + 10224040996 = 1095855^2 + 101114^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211122222021 - 2¹ = 1211122222019 is a prime.

Together with 1211122222019, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 1211122222021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1211122222027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605561111010 + 605561111011.

It is an arithmetic number, because the mean of its divisors is an integer number (605561111011).

Almost surely, 2^{1211122222021} is an apocalyptic number.

It is an amenable number.

1211122222021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211122222021 is an equidigital number, since it uses as much as digits as its factorization.

1211122222021 is an odious number, because the sum of its binary digits is odd.

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

Adding to 1211122222021 its reverse (1202222211121), we get a palindrome (2413344433142).

The spelling of 1211122222021 in words is "one trillion, two hundred eleven billion, one hundred twenty-two million, two hundred twenty-two thousand, twenty-one".