11515321121 has 4 divisors (see below), whose sum is σ = 11515543572. Its totient is φ = 11515098672.

The previous prime is 11515321117. The next prime is 11515321171. The reversal of 11515321121 is 12112351511.

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 1427328400 + 10087992721 = 37780^2 + 100439^2 .

It is a cyclic number.

It is not a de Polignac number, because 11515321121 - 2² = 11515321117 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11515321171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11735 + ... + 152211.

It is an arithmetic number, because the mean of its divisors is an integer number (2878885893).

Almost surely, 2^11515321121 is an apocalyptic number.

It is an amenable number.

11515321121 is a deficient number, since it is larger than the sum of its proper divisors (222451).

11515321121 is an equidigital number, since it uses as much as digits as its factorization.

11515321121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222450.

The product of its digits is 300, while the sum is 23.

Adding to 11515321121 its reverse (12112351511), we get a palindrome (23627672632).

The spelling of 11515321121 in words is "eleven billion, five hundred fifteen million, three hundred twenty-one thousand, one hundred twenty-one".