205420517 has 2 divisors, whose sum is σ = 205420518. Its totient is φ = 205420516.

The previous prime is 205420507. The next prime is 205420541. The reversal of 205420517 is 715024502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 205091041 + 329476 = 14321^2 + 574^2 .

It is a cyclic number.

It is not a de Polignac number, because 205420517 - 2¹⁰ = 205419493 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (205420507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102710258 + 102710259.

It is an arithmetic number, because the mean of its divisors is an integer number (102710259).

Almost surely, 2^205420517 is an apocalyptic number.

It is an amenable number.

205420517 is a deficient number, since it is larger than the sum of its proper divisors (1).

205420517 is an equidigital number, since it uses as much as digits as its factorization.

205420517 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2800, while the sum is 26.

The square root of 205420517 is about 14332.4986307343. The cubic root of 205420517 is about 590.0397531387.

The spelling of 205420517 in words is "two hundred five million, four hundred twenty thousand, five hundred seventeen".