11111121209 has 2 divisors, whose sum is σ = 11111121210. Its totient is φ = 11111121208.

The previous prime is 11111121193. The next prime is 11111121211. The reversal of 11111121209 is 90212111111.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7258188025 + 3852933184 = 85195^2 + 62072^2 .

It is a cyclic number.

It is not a de Polignac number, because 11111121209 - 2⁴ = 11111121193 is a prime.

Together with 11111121211, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (11111121289) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5555560604 + 5555560605.

It is an arithmetic number, because the mean of its divisors is an integer number (5555560605).

Almost surely, 2^11111121209 is an apocalyptic number.

It is an amenable number.

11111121209 is a deficient number, since it is larger than the sum of its proper divisors (1).

11111121209 is an equidigital number, since it uses as much as digits as its factorization.

11111121209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36, while the sum is 20.

The spelling of 11111121209 in words is "eleven billion, one hundred eleven million, one hundred twenty-one thousand, two hundred nine".