4243123121 has 2 divisors, whose sum is σ = 4243123122. Its totient is φ = 4243123120.

The previous prime is 4243123097. The next prime is 4243123127. The reversal of 4243123121 is 1213213424.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3992344225 + 250778896 = 63185^2 + 15836^2 .

It is a cyclic number.

It is not a de Polignac number, because 4243123121 - 2¹⁰ = 4243122097 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (4243123127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2121561560 + 2121561561.

It is an arithmetic number, because the mean of its divisors is an integer number (2121561561).

Almost surely, 2^4243123121 is an apocalyptic number.

It is an amenable number.

4243123121 is a deficient number, since it is larger than the sum of its proper divisors (1).

4243123121 is an equidigital number, since it uses as much as digits as its factorization.

4243123121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1152, while the sum is 23.

The square root of 4243123121 is about 65139.2594446698. The cubic root of 4243123121 is about 1618.9317655276.

Adding to 4243123121 its reverse (1213213424), we get a palindrome (5456336545).

The spelling of 4243123121 in words is "four billion, two hundred forty-three million, one hundred twenty-three thousand, one hundred twenty-one".