205609972417 has 2 divisors, whose sum is σ = 205609972418. Its totient is φ = 205609972416.

The previous prime is 205609972357. The next prime is 205609972423. The reversal of 205609972417 is 714279906502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 113245037361 + 92364935056 = 336519^2 + 303916^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-205609972417 is a prime.

It is not a weakly prime, because it can be changed into another prime (205609972427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102804986208 + 102804986209.

It is an arithmetic number, because the mean of its divisors is an integer number (102804986209).

Almost surely, 2^205609972417 is an apocalyptic number.

It is an amenable number.

205609972417 is a deficient number, since it is larger than the sum of its proper divisors (1).

205609972417 is an equidigital number, since it uses as much as digits as its factorization.

205609972417 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1905120, while the sum is 52.

The spelling of 205609972417 in words is "two hundred five billion, six hundred nine million, nine hundred seventy-two thousand, four hundred seventeen".