205105891 has 2 divisors, whose sum is σ = 205105892. Its totient is φ = 205105890.

The previous prime is 205105877. The next prime is 205105913. The reversal of 205105891 is 198501502.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 205105891 - 2⁹ = 205105379 is a prime.

It is not a weakly prime, because it can be changed into another prime (205105841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102552945 + 102552946.

It is an arithmetic number, because the mean of its divisors is an integer number (102552946).

Almost surely, 2^205105891 is an apocalyptic number.

205105891 is a deficient number, since it is larger than the sum of its proper divisors (1).

205105891 is an equidigital number, since it uses as much as digits as its factorization.

205105891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3600, while the sum is 31.

The square root of 205105891 is about 14321.5184599958. The cubic root of 205105891 is about 589.7383604828.

The spelling of 205105891 in words is "two hundred five million, one hundred five thousand, eight hundred ninety-one".