211203209509 has 2 divisors, whose sum is σ = 211203209510. Its totient is φ = 211203209508.

The previous prime is 211203209489. The next prime is 211203209551. The reversal of 211203209509 is 905902302112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 199299744900 + 11903464609 = 446430^2 + 109103^2 .

It is a cyclic number.

It is not a de Polignac number, because 211203209509 - 2¹¹ = 211203207461 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211203209909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105601604754 + 105601604755.

It is an arithmetic number, because the mean of its divisors is an integer number (105601604755).

Almost surely, 2^211203209509 is an apocalyptic number.

It is an amenable number.

211203209509 is a deficient number, since it is larger than the sum of its proper divisors (1).

211203209509 is an equidigital number, since it uses as much as digits as its factorization.

211203209509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9720, while the sum is 34.

The spelling of 211203209509 in words is "two hundred eleven billion, two hundred three million, two hundred nine thousand, five hundred nine".