2120001809 has 2 divisors, whose sum is σ = 2120001810. Its totient is φ = 2120001808.

The previous prime is 2120001791. The next prime is 2120001811. The reversal of 2120001809 is 9081000212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1166427409 + 953574400 = 34153^2 + 30880^2 .

It is a cyclic number.

It is not a de Polignac number, because 2120001809 - 2⁸ = 2120001553 is a prime.

Together with 2120001811, 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 (2120001859) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1060000904 + 1060000905.

It is an arithmetic number, because the mean of its divisors is an integer number (1060000905).

Almost surely, 2^2120001809 is an apocalyptic number.

It is an amenable number.

2120001809 is a deficient number, since it is larger than the sum of its proper divisors (1).

2120001809 is an equidigital number, since it uses as much as digits as its factorization.

2120001809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 2120001809 is about 46043.4773773658. The cubic root of 2120001809 is about 1284.6320231052.

The spelling of 2120001809 in words is "two billion, one hundred twenty million, one thousand, eight hundred nine".