1211220112121 has 2 divisors, whose sum is σ = 1211220112122. Its totient is φ = 1211220112120.

The previous prime is 1211220112097. The next prime is 1211220112153. The reversal of 1211220112121 is 1212110221121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 752669029225 + 458551082896 = 867565^2 + 677164^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211220112121 - 2²² = 1211215917817 is a prime.

It is a super-2 number, since 2×1211220112121² (a number of 25 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1211220112121.

It is not a weakly prime, because it can be changed into another prime (1211220112021) 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, 605610056060 + 605610056061.

It is an arithmetic number, because the mean of its divisors is an integer number (605610056061).

Almost surely, 2^{1211220112121} is an apocalyptic number.

It is an amenable number.

1211220112121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211220112121 is an equidigital number, since it uses as much as digits as its factorization.

1211220112121 is an odious number, because the sum of its binary digits is odd.

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

Adding to 1211220112121 its reverse (1212110221121), we get a palindrome (2423330333242).

The spelling of 1211220112121 in words is "one trillion, two hundred eleven billion, two hundred twenty million, one hundred twelve thousand, one hundred twenty-one".