111543431521 has 4 divisors (see below), whose sum is σ = 111567956500. Its totient is φ = 111518906544.

The previous prime is 111543431501. The next prime is 111543431621. The reversal of 111543431521 is 125134345111.

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 76839840000 + 34703591521 = 277200^2 + 186289^2 .

It is a cyclic number.

It is not a de Polignac number, because 111543431521 - 2⁹ = 111543431009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (111543431501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12255666 + ... + 12264763.

It is an arithmetic number, because the mean of its divisors is an integer number (27891989125).

Almost surely, 2^111543431521 is an apocalyptic number.

It is an amenable number.

111543431521 is a deficient number, since it is larger than the sum of its proper divisors (24524979).

111543431521 is an equidigital number, since it uses as much as digits as its factorization.

111543431521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24524978.

The product of its digits is 7200, while the sum is 31.

Adding to 111543431521 its reverse (125134345111), we get a palindrome (236677776632).

The spelling of 111543431521 in words is "one hundred eleven billion, five hundred forty-three million, four hundred thirty-one thousand, five hundred twenty-one".