121212011909 has 2 divisors, whose sum is σ = 121212011910. Its totient is φ = 121212011908.

The previous prime is 121212011897. The next prime is 121212011911. The reversal of 121212011909 is 909110212121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 84752018884 + 36459993025 = 291122^2 + 190945^2 .

It is a cyclic number.

It is not a de Polignac number, because 121212011909 - 2⁸ = 121212011653 is a prime.

It is a Sophie Germain prime.

Together with 121212011911, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121212011939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60606005954 + 60606005955.

It is an arithmetic number, because the mean of its divisors is an integer number (60606005955).

Almost surely, 2^121212011909 is an apocalyptic number.

It is an amenable number.

121212011909 is a deficient number, since it is larger than the sum of its proper divisors (1).

121212011909 is an equidigital number, since it uses as much as digits as its factorization.

121212011909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 29.

The spelling of 121212011909 in words is "one hundred twenty-one billion, two hundred twelve million, eleven thousand, nine hundred nine".