12789121909 has 2 divisors, whose sum is σ = 12789121910. Its totient is φ = 12789121908.

The previous prime is 12789121907. The next prime is 12789121931. The reversal of 12789121909 is 90912198721.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12741442884 + 47679025 = 112878^2 + 6905^2 .

It is a cyclic number.

It is not a de Polignac number, because 12789121909 - 2¹ = 12789121907 is a prime.

Together with 12789121907, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12789121907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6394560954 + 6394560955.

It is an arithmetic number, because the mean of its divisors is an integer number (6394560955).

Almost surely, 2^12789121909 is an apocalyptic number.

It is an amenable number.

12789121909 is a deficient number, since it is larger than the sum of its proper divisors (1).

12789121909 is an equidigital number, since it uses as much as digits as its factorization.

12789121909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 163296, while the sum is 49.

It can be divided in two parts, 1278912 and 1909, that added together give a palindrome (1280821).

The spelling of 12789121909 in words is "twelve billion, seven hundred eighty-nine million, one hundred twenty-one thousand, nine hundred nine".