12423443121 has 20 divisors (see below), whose sum is σ = 19060061812. Its totient is φ = 8058447648.

The previous prime is 12423443057. The next prime is 12423443129. The reversal of 12423443121 is 12134432421.

12423443121 is a `hidden beast` number, since 1 + 2 + 4 + 2 + 344 + 312 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 7342604721 + 5080838400 = 85689^2 + 71280^2 .

It is not a de Polignac number, because 12423443121 - 2⁶ = 12423443057 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12423443129) 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 19 ways as a sum of consecutive naturals, for example, 2069650 + ... + 2075643.

Almost surely, 2^12423443121 is an apocalyptic number.

It is an amenable number.

12423443121 is a deficient number, since it is larger than the sum of its proper divisors (6636618691).

12423443121 is an equidigital number, since it uses as much as digits as its factorization.

12423443121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4145342 (or 4145333 counting only the distinct ones).

The product of its digits is 4608, while the sum is 27.

Adding to 12423443121 its reverse (12134432421), we get a palindrome (24557875542).

The spelling of 12423443121 in words is "twelve billion, four hundred twenty-three million, four hundred forty-three thousand, one hundred twenty-one".