211111647809 has 2 divisors, whose sum is σ = 211111647810. Its totient is φ = 211111647808.

The previous prime is 211111647779. The next prime is 211111647863. The reversal of 211111647809 is 908746111112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 106947312784 + 104164335025 = 327028^2 + 322745^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-211111647809 is a prime.

It is not a weakly prime, because it can be changed into another prime (211111647869) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105555823904 + 105555823905.

It is an arithmetic number, because the mean of its divisors is an integer number (105555823905).

Almost surely, 2^211111647809 is an apocalyptic number.

It is an amenable number.

211111647809 is a deficient number, since it is larger than the sum of its proper divisors (1).

211111647809 is an equidigital number, since it uses as much as digits as its factorization.

211111647809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24192, while the sum is 41.

The spelling of 211111647809 in words is "two hundred eleven billion, one hundred eleven million, six hundred forty-seven thousand, eight hundred nine".