11531123121 has 16 divisors (see below), whose sum is σ = 17591298944. Its totient is φ = 6581689344.

The previous prime is 11531123119. The next prime is 11531123129. The reversal of 11531123121 is 12132113511.

It is not a de Polignac number, because 11531123121 - 2¹ = 11531123119 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11531123129) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 294640 + ... + 331473.

It is an arithmetic number, because the mean of its divisors is an integer number (1099456184).

Almost surely, 2^11531123121 is an apocalyptic number.

It is an amenable number.

11531123121 is a deficient number, since it is larger than the sum of its proper divisors (6060175823).

11531123121 is an equidigital number, since it uses as much as digits as its factorization.

11531123121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 627000.

The product of its digits is 180, while the sum is 21.

Adding to 11531123121 its reverse (12132113511), we get a palindrome (23663236632).

The spelling of 11531123121 in words is "eleven billion, five hundred thirty-one million, one hundred twenty-three thousand, one hundred twenty-one".