9911806232509 has 2 divisors, whose sum is σ = 9911806232510. Its totient is φ = 9911806232508.

The previous prime is 9911806232501. The next prime is 9911806232557. The reversal of 9911806232509 is 9052326081199.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9870687315225 + 41118917284 = 3141765^2 + 202778^2 .

It is a cyclic number.

It is not a de Polignac number, because 9911806232509 - 2³ = 9911806232501 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 9911806232509.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9911806232501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4955903116254 + 4955903116255.

It is an arithmetic number, because the mean of its divisors is an integer number (4955903116255).

Almost surely, 2^{9911806232509} is an apocalyptic number.

It is an amenable number.

9911806232509 is a deficient number, since it is larger than the sum of its proper divisors (1).

9911806232509 is an equidigital number, since it uses as much as digits as its factorization.

9911806232509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2099520, while the sum is 55.

The spelling of 9911806232509 in words is "nine trillion, nine hundred eleven billion, eight hundred six million, two hundred thirty-two thousand, five hundred nine".