205601609 has 2 divisors, whose sum is σ = 205601610. Its totient is φ = 205601608.

The previous prime is 205601597. The next prime is 205601629. The reversal of 205601609 is 906106502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 161671225 + 43930384 = 12715^2 + 6628^2 .

It is a cyclic number.

It is not a de Polignac number, because 205601609 - 2²⁰ = 204553033 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (205601629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102800804 + 102800805.

It is an arithmetic number, because the mean of its divisors is an integer number (102800805).

Almost surely, 2^205601609 is an apocalyptic number.

It is an amenable number.

205601609 is a deficient number, since it is larger than the sum of its proper divisors (1).

205601609 is an equidigital number, since it uses as much as digits as its factorization.

205601609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3240, while the sum is 29.

The square root of 205601609 is about 14338.8147697081. The cubic root of 205601609 is about 590.2130887870.

The spelling of 205601609 in words is "two hundred five million, six hundred one thousand, six hundred nine".