243404020121 has 2 divisors, whose sum is σ = 243404020122. Its totient is φ = 243404020120.

The previous prime is 243404020091. The next prime is 243404020177. The reversal of 243404020121 is 121020404342.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 144172090000 + 99231930121 = 379700^2 + 315011^2 .

It is a cyclic number.

It is not a de Polignac number, because 243404020121 - 2¹⁴ = 243404003737 is a prime.

It is a super-2 number, since 2×243404020121² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (243404020621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121702010060 + 121702010061.

It is an arithmetic number, because the mean of its divisors is an integer number (121702010061).

Almost surely, 2^243404020121 is an apocalyptic number.

It is an amenable number.

243404020121 is a deficient number, since it is larger than the sum of its proper divisors (1).

243404020121 is an equidigital number, since it uses as much as digits as its factorization.

243404020121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1536, while the sum is 23.

Adding to 243404020121 its reverse (121020404342), we get a palindrome (364424424463).

The spelling of 243404020121 in words is "two hundred forty-three billion, four hundred four million, twenty thousand, one hundred twenty-one".