11121213121 has 4 divisors (see below), whose sum is σ = 11231324244. Its totient is φ = 11011102000.

The previous prime is 11121213049. The next prime is 11121213127. The reversal of 11121213121 is 12131212111.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8452044225 + 2669168896 = 91935^2 + 51664^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11121213121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 11121213095 and 11121213104.

It is not an unprimeable number, because it can be changed into a prime (11121213127) 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, 55055410 + ... + 55055611.

It is an arithmetic number, because the mean of its divisors is an integer number (2807831061).

Almost surely, 2^11121213121 is an apocalyptic number.

It is an amenable number.

11121213121 is a deficient number, since it is larger than the sum of its proper divisors (110111123).

11121213121 is a wasteful number, since it uses less digits than its factorization.

11121213121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110111122.

The product of its digits is 24, while the sum is 16.

Adding to 11121213121 its reverse (12131212111), we get a palindrome (23252425232).

The spelling of 11121213121 in words is "eleven billion, one hundred twenty-one million, two hundred thirteen thousand, one hundred twenty-one".