11111211121 has 2 divisors, whose sum is σ = 11111211122. Its totient is φ = 11111211120.

The previous prime is 11111211073. The next prime is 11111211127. The reversal of 11111211121 is 12111211111.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7578573025 + 3532638096 = 87055^2 + 59436^2 .

It is a cyclic number.

It is not a de Polignac number, because 11111211121 - 2⁹ = 11111210609 is a prime.

It is not a weakly prime, because it can be changed into another prime (11111211127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5555605560 + 5555605561.

It is an arithmetic number, because the mean of its divisors is an integer number (5555605561).

Almost surely, 2^11111211121 is an apocalyptic number.

It is an amenable number.

11111211121 is a deficient number, since it is larger than the sum of its proper divisors (1).

11111211121 is an equidigital number, since it uses as much as digits as its factorization.

11111211121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4, while the sum is 13.

Adding to 11111211121 its reverse (12111211111), we get a palindrome (23222422232).

It can be divided in two parts, 1111 and 1211121, that multiplied together give a palindrome (1345555431).

The spelling of 11111211121 in words is "eleven billion, one hundred eleven million, two hundred eleven thousand, one hundred twenty-one".