205965879834509 has 2 divisors, whose sum is σ = 205965879834510. Its totient is φ = 205965879834508.

The previous prime is 205965879834469. The next prime is 205965879834541. The reversal of 205965879834509 is 905438978569502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 184383211973284 + 21582667861225 = 13578778^2 + 4645715^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-205965879834509 is a prime.

It is a super-2 number, since 2×205965879834509² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (205965869834509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102982939917254 + 102982939917255.

It is an arithmetic number, because the mean of its divisors is an integer number (102982939917255).

Almost surely, 2^{205965879834509} is an apocalyptic number.

It is an amenable number.

205965879834509 is a deficient number, since it is larger than the sum of its proper divisors (1).

205965879834509 is an equidigital number, since it uses as much as digits as its factorization.

205965879834509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5878656000, while the sum is 80.

The spelling of 205965879834509 in words is "two hundred five trillion, nine hundred sixty-five billion, eight hundred seventy-nine million, eight hundred thirty-four thousand, five hundred nine".