205440397 has 2 divisors, whose sum is σ = 205440398. Its totient is φ = 205440396.

The previous prime is 205440383. The next prime is 205440413. The reversal of 205440397 is 793044502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 194490916 + 10949481 = 13946^2 + 3309^2 .

It is a cyclic number.

It is not a de Polignac number, because 205440397 - 2¹⁹ = 204916109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (205440307) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102720198 + 102720199.

It is an arithmetic number, because the mean of its divisors is an integer number (102720199).

Almost surely, 2^205440397 is an apocalyptic number.

It is an amenable number.

205440397 is a deficient number, since it is larger than the sum of its proper divisors (1).

205440397 is an equidigital number, since it uses as much as digits as its factorization.

205440397 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 30240, while the sum is 34.

The square root of 205440397 is about 14333.1921427155. The cubic root of 205440397 is about 590.0587866350.

Adding to 205440397 its reverse (793044502), we get a palindrome (998484899).

The spelling of 205440397 in words is "two hundred five million, four hundred forty thousand, three hundred ninety-seven".