11123213121 has 12 divisors (see below), whose sum is σ = 16458738660. Its totient is φ = 7234609920.

The previous prime is 11123213119. The next prime is 11123213131. The reversal of 11123213121 is 12131232111.

It can be written as a sum of positive squares in 2 ways, for example, as 787644225 + 10335568896 = 28065^2 + 101664^2 .

It is not a de Polignac number, because 11123213121 - 2¹ = 11123213119 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 11123213094 and 11123213103.

It is not an unprimeable number, because it can be changed into a prime (11123213131) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15071736 + ... + 15072473.

It is an arithmetic number, because the mean of its divisors is an integer number (1371561555).

Almost surely, 2^11123213121 is an apocalyptic number.

It is an amenable number.

11123213121 is a deficient number, since it is larger than the sum of its proper divisors (5335525539).

11123213121 is a wasteful number, since it uses less digits than its factorization.

11123213121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30144256 (or 30144253 counting only the distinct ones).

The product of its digits is 72, while the sum is 18.

Adding to 11123213121 its reverse (12131232111), we get a palindrome (23254445232).

The spelling of 11123213121 in words is "eleven billion, one hundred twenty-three million, two hundred thirteen thousand, one hundred twenty-one".