243120340521 has 6 divisors (see below), whose sum is σ = 351173825210. Its totient is φ = 162080227008.

The previous prime is 243120340471. The next prime is 243120340621. The reversal of 243120340521 is 125043021342.

243120340521 is a `hidden beast` number, since 2 + 4 + 31 + 203 + 405 + 21 = 666.

It can be written as a sum of positive squares in only one way, i.e., 231876919296 + 11243421225 = 481536^2 + 106035^2 .

It is not a de Polignac number, because 243120340521 - 2¹⁵ = 243120307753 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (243120340621) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 13506685576 + ... + 13506685593.

Almost surely, 2^243120340521 is an apocalyptic number.

It is an amenable number.

243120340521 is a deficient number, since it is larger than the sum of its proper divisors (108053484689).

243120340521 is a wasteful number, since it uses less digits than its factorization.

243120340521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27013371175 (or 27013371172 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 27.

Adding to 243120340521 its reverse (125043021342), we get a palindrome (368163361863).

The spelling of 243120340521 in words is "two hundred forty-three billion, one hundred twenty million, three hundred forty thousand, five hundred twenty-one".