243120353521 has 2 divisors, whose sum is σ = 243120353522. Its totient is φ = 243120353520.

The previous prime is 243120353503. The next prime is 243120353551. The reversal of 243120353521 is 125353021342.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 242813403121 + 306950400 = 492761^2 + 17520^2 .

It is a cyclic number.

It is not a de Polignac number, because 243120353521 - 2¹⁹ = 243119829233 is a prime.

It is not a weakly prime, because it can be changed into another prime (243120353551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121560176760 + 121560176761.

It is an arithmetic number, because the mean of its divisors is an integer number (121560176761).

Almost surely, 2^243120353521 is an apocalyptic number.

It is an amenable number.

243120353521 is a deficient number, since it is larger than the sum of its proper divisors (1).

243120353521 is an equidigital number, since it uses as much as digits as its factorization.

243120353521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 21600, while the sum is 31.

Adding to 243120353521 its reverse (125353021342), we get a palindrome (368473374863).

The spelling of 243120353521 in words is "two hundred forty-three billion, one hundred twenty million, three hundred fifty-three thousand, five hundred twenty-one".