205191 has 12 divisors (see below), whose sum is σ = 338832. Its totient is φ = 117216.

The previous prime is 205187. The next prime is 205201. The reversal of 205191 is 191502.

It is not a de Polignac number, because 205191 - 2² = 205187 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205111) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1566 + ... + 1691.

It is an arithmetic number, because the mean of its divisors is an integer number (28236).

2²⁰⁵¹⁹¹ is an apocalyptic number.

205191 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

205191 is a deficient number, since it is larger than the sum of its proper divisors (133641).

205191 is a wasteful number, since it uses less digits than its factorization.

205191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3270 (or 3267 counting only the distinct ones).

The product of its (nonzero) digits is 90, while the sum is 18.

The square root of 205191 is about 452.9801320146. The cubic root of 205191 is about 58.9819920145.

Adding to 205191 its sum of digits (18), we get a square (205209 = 453²).

Adding to 205191 its reverse (191502), we get a palindrome (396693).

Subtracting from 205191 its reverse (191502), we obtain a square (13689 = 117²).

The spelling of 205191 in words is "two hundred five thousand, one hundred ninety-one".