205101509 has 2 divisors, whose sum is σ = 205101510. Its totient is φ = 205101508.

The previous prime is 205101499. The next prime is 205101521. The reversal of 205101509 is 905101502.

205101509 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 188925025 + 16176484 = 13745^2 + 4022^2 .

It is a cyclic number.

It is not a de Polignac number, because 205101509 - 2⁴ = 205101493 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (205101569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102550754 + 102550755.

It is an arithmetic number, because the mean of its divisors is an integer number (102550755).

Almost surely, 2^205101509 is an apocalyptic number.

It is an amenable number.

205101509 is a deficient number, since it is larger than the sum of its proper divisors (1).

205101509 is an equidigital number, since it uses as much as digits as its factorization.

205101509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 450, while the sum is 23.

The square root of 205101509 is about 14321.3654726077. The cubic root of 205101509 is about 589.7341606166.

The spelling of 205101509 in words is "two hundred five million, one hundred one thousand, five hundred nine".