205217291 has 2 divisors, whose sum is σ = 205217292. Its totient is φ = 205217290.

The previous prime is 205217267. The next prime is 205217297. The reversal of 205217291 is 192712502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 205217291 - 2⁶ = 205217227 is a prime.

It is a super-2 number, since 2×205217291² = 84228273050757362, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (205217297) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102608645 + 102608646.

It is an arithmetic number, because the mean of its divisors is an integer number (102608646).

Almost surely, 2^205217291 is an apocalyptic number.

205217291 is a deficient number, since it is larger than the sum of its proper divisors (1).

205217291 is an equidigital number, since it uses as much as digits as its factorization.

205217291 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2520, while the sum is 29.

The square root of 205217291 is about 14325.4071844398. The cubic root of 205217291 is about 589.8451101598.

Adding to 205217291 its reverse (192712502), we get a palindrome (397929793).

The spelling of 205217291 in words is "two hundred five million, two hundred seventeen thousand, two hundred ninety-one".