11121222121 has 4 divisors (see below), whose sum is σ = 11148956244. Its totient is φ = 11093488000.

The previous prime is 11121222107. The next prime is 11121222173. The reversal of 11121222121 is 12122212111.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12122212111 = 389 ⋅31162499.

It can be written as a sum of positive squares in 2 ways, for example, as 11051265625 + 69956496 = 105125^2 + 8364^2 .

It is a cyclic number.

It is not a de Polignac number, because 11121222121 - 2⁵ = 11121222089 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 11121222095 and 11121222104.

It is not an unprimeable number, because it can be changed into a prime (11121222421) 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, 13866460 + ... + 13867261.

It is an arithmetic number, because the mean of its divisors is an integer number (2787239061).

Almost surely, 2^11121222121 is an apocalyptic number.

It is an amenable number.

11121222121 is a deficient number, since it is larger than the sum of its proper divisors (27734123).

11121222121 is an equidigital number, since it uses as much as digits as its factorization.

11121222121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27734122.

The product of its digits is 32, while the sum is 16.

Adding to 11121222121 its reverse (12122212111), we get a palindrome (23243434232).

It can be divided in two parts, 11 and 121222121, that multiplied together give a palindrome (1333443331).

The spelling of 11121222121 in words is "eleven billion, one hundred twenty-one million, two hundred twenty-two thousand, one hundred twenty-one".