111212121121 has 4 divisors (see below), whose sum is σ = 113578336512. Its totient is φ = 108845905732.

The previous prime is 111212121107. The next prime is 111212121187. The reversal of 111212121121 is 121121212111.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 111212121121 - 2¹⁹ = 111211596833 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 111212121095 and 111212121104.

It is not an unprimeable number, because it can be changed into a prime (111212151121) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1183107625 + ... + 1183107718.

It is an arithmetic number, because the mean of its divisors is an integer number (28394584128).

Almost surely, 2^111212121121 is an apocalyptic number.

It is an amenable number.

111212121121 is a deficient number, since it is larger than the sum of its proper divisors (2366215391).

111212121121 is an equidigital number, since it uses as much as digits as its factorization.

111212121121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2366215390.

The product of its digits is 16, while the sum is 16.

Adding to 111212121121 its reverse (121121212111), we get a palindrome (232333333232).

The spelling of 111212121121 in words is "one hundred eleven billion, two hundred twelve million, one hundred twenty-one thousand, one hundred twenty-one".