12105816817 has 2 divisors, whose sum is σ = 12105816818. Its totient is φ = 12105816816.

The previous prime is 12105816809. The next prime is 12105816823. The reversal of 12105816817 is 71861850121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6743037456 + 5362779361 = 82116^2 + 73231^2 .

It is an emirp because it is prime and its reverse (71861850121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12105816817 - 2³ = 12105816809 is a prime.

It is a super-2 number, since 2×12105816817² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 12105816817.

It is not a weakly prime, because it can be changed into another prime (12105816887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6052908408 + 6052908409.

It is an arithmetic number, because the mean of its divisors is an integer number (6052908409).

Almost surely, 2^12105816817 is an apocalyptic number.

It is an amenable number.

12105816817 is a deficient number, since it is larger than the sum of its proper divisors (1).

12105816817 is an equidigital number, since it uses as much as digits as its factorization.

12105816817 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 26880, while the sum is 40.

The spelling of 12105816817 in words is "twelve billion, one hundred five million, eight hundred sixteen thousand, eight hundred seventeen".