205555391 has 2 divisors, whose sum is σ = 205555392. Its totient is φ = 205555390.

The previous prime is 205555373. The next prime is 205555403. The reversal of 205555391 is 193555502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 205555391 - 2¹⁴ = 205539007 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (205555291) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102777695 + 102777696.

It is an arithmetic number, because the mean of its divisors is an integer number (102777696).

Almost surely, 2^205555391 is an apocalyptic number.

205555391 is a deficient number, since it is larger than the sum of its proper divisors (1).

205555391 is an equidigital number, since it uses as much as digits as its factorization.

205555391 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 33750, while the sum is 35.

The square root of 205555391 is about 14337.2030396448. The cubic root of 205555391 is about 590.1688600267.

The spelling of 205555391 in words is "two hundred five million, five hundred fifty-five thousand, three hundred ninety-one".