2011209509 has 2 divisors, whose sum is σ = 2011209510. Its totient is φ = 2011209508.

The previous prime is 2011209491. The next prime is 2011209511. The reversal of 2011209509 is 9059021102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1724076484 + 287133025 = 41522^2 + 16945^2 .

It is a cyclic number.

It is not a de Polignac number, because 2011209509 - 2⁸ = 2011209253 is a prime.

Together with 2011209511, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2011209559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1005604754 + 1005604755.

It is an arithmetic number, because the mean of its divisors is an integer number (1005604755).

Almost surely, 2^2011209509 is an apocalyptic number.

It is an amenable number.

2011209509 is a deficient number, since it is larger than the sum of its proper divisors (1).

2011209509 is an equidigital number, since it uses as much as digits as its factorization.

2011209509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1620, while the sum is 29.

The square root of 2011209509 is about 44846.5105554490. The cubic root of 2011209509 is about 1262.2705153456.

The spelling of 2011209509 in words is "two billion, eleven million, two hundred nine thousand, five hundred nine".