11211121212121 has 2 divisors, whose sum is σ = 11211121212122. Its totient is φ = 11211121212120.

The previous prime is 11211121212101. The next prime is 11211121212143. The reversal of 11211121212121 is 12121212111211.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11129990234896 + 81130977225 = 3336164^2 + 284835^2 .

It is a cyclic number.

It is not a de Polignac number, because 11211121212121 - 2⁷ = 11211121211993 is a prime.

It is not a weakly prime, because it can be changed into another prime (11211121212101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5605560606060 + 5605560606061.

It is an arithmetic number, because the mean of its divisors is an integer number (5605560606061).

Almost surely, 2^{11211121212121} is an apocalyptic number.

It is an amenable number.

11211121212121 is a deficient number, since it is larger than the sum of its proper divisors (1).

11211121212121 is an equidigital number, since it uses as much as digits as its factorization.

11211121212121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 32, while the sum is 19.

Adding to 11211121212121 its reverse (12121212111211), we get a palindrome (23332333323332).

The spelling of 11211121212121 in words is "eleven trillion, two hundred eleven billion, one hundred twenty-one million, two hundred twelve thousand, one hundred twenty-one".