243115554509 has 2 divisors, whose sum is σ = 243115554510. Its totient is φ = 243115554508.

The previous prime is 243115554491. The next prime is 243115554529. The reversal of 243115554509 is 905455511342.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 193729381609 + 49386172900 = 440147^2 + 222230^2 .

It is a cyclic number.

It is not a de Polignac number, because 243115554509 - 2²⁴ = 243098777293 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 243115554509.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (243115554529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121557777254 + 121557777255.

It is an arithmetic number, because the mean of its divisors is an integer number (121557777255).

Almost surely, 2^243115554509 is an apocalyptic number.

It is an amenable number.

243115554509 is a deficient number, since it is larger than the sum of its proper divisors (1).

243115554509 is an equidigital number, since it uses as much as digits as its factorization.

243115554509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 540000, while the sum is 44.

The spelling of 243115554509 in words is "two hundred forty-three billion, one hundred fifteen million, five hundred fifty-four thousand, five hundred nine".