9905209 has 2 divisors, whose sum is σ = 9905210. Its totient is φ = 9905208.

The previous prime is 9905197. The next prime is 9905221. The reversal of 9905209 is 9025099.

9905209 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a balanced prime because it is at equal distance from previous prime (9905197) and next prime (9905221).

It can be written as a sum of positive squares in only one way, i.e., 9903609 + 1600 = 3147^2 + 40^2 .

It is an emirp because it is prime and its reverse (9025099) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9905209 - 2⁵ = 9905177 is a prime.

It is a super-2 number, since 2×9905209² = 196226330667362, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (9905239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4952604 + 4952605.

It is an arithmetic number, because the mean of its divisors is an integer number (4952605).

Almost surely, 2^9905209 is an apocalyptic number.

It is an amenable number.

9905209 is a deficient number, since it is larger than the sum of its proper divisors (1).

9905209 is an equidigital number, since it uses as much as digits as its factorization.

9905209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7290, while the sum is 34.

The square root of 9905209 is about 3147.2542000925. The cubic root of 9905209 is about 214.7605699511.

The spelling of 9905209 in words is "nine million, nine hundred five thousand, two hundred nine".