11911959809 has 2 divisors, whose sum is σ = 11911959810. Its totient is φ = 11911959808.

The previous prime is 11911959781. The next prime is 11911959817. The reversal of 11911959809 is 90895911911.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10444840000 + 1467119809 = 102200^2 + 38303^2 .

It is a cyclic number.

It is not a de Polignac number, because 11911959809 - 2²⁸ = 11643524353 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (11911949809) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5955979904 + 5955979905.

It is an arithmetic number, because the mean of its divisors is an integer number (5955979905).

Almost surely, 2^11911959809 is an apocalyptic number.

It is an amenable number.

11911959809 is a deficient number, since it is larger than the sum of its proper divisors (1).

11911959809 is an equidigital number, since it uses as much as digits as its factorization.

11911959809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 262440, while the sum is 53.

The spelling of 11911959809 in words is "eleven billion, nine hundred eleven million, nine hundred fifty-nine thousand, eight hundred nine".