205511513 has 2 divisors, whose sum is σ = 205511514. Its totient is φ = 205511512.

The previous prime is 205511503. The next prime is 205511531. The reversal of 205511513 is 315115502.

It is a happy number.

Together with next prime (205511531) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 127418944 + 78092569 = 11288^2 + 8837^2 .

It is a cyclic number.

It is not a de Polignac number, because 205511513 - 2⁴ = 205511497 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (205511503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102755756 + 102755757.

It is an arithmetic number, because the mean of its divisors is an integer number (102755757).

Almost surely, 2^205511513 is an apocalyptic number.

It is an amenable number.

205511513 is a deficient number, since it is larger than the sum of its proper divisors (1).

205511513 is an equidigital number, since it uses as much as digits as its factorization.

205511513 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 750, while the sum is 23.

The square root of 205511513 is about 14335.6727431956. The cubic root of 205511513 is about 590.1268644169.

The spelling of 205511513 in words is "two hundred five million, five hundred eleven thousand, five hundred thirteen".