205105009 has 2 divisors, whose sum is σ = 205105010. Its totient is φ = 205105008.

The previous prime is 205105003. The next prime is 205105067. The reversal of 205105009 is 900501502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 159946609 + 45158400 = 12647^2 + 6720^2 .

It is a cyclic number.

It is not a de Polignac number, because 205105009 - 2¹⁹ = 204580721 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (205105003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102552504 + 102552505.

It is an arithmetic number, because the mean of its divisors is an integer number (102552505).

Almost surely, 2^205105009 is an apocalyptic number.

It is an amenable number.

205105009 is a deficient number, since it is larger than the sum of its proper divisors (1).

205105009 is an equidigital number, since it uses as much as digits as its factorization.

205105009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 450, while the sum is 22.

The square root of 205105009 is about 14321.4876671385. The cubic root of 205105009 is about 589.7375151471.

The spelling of 205105009 in words is "two hundred five million, one hundred five thousand, nine".