205949 has 2 divisors, whose sum is σ = 205950. Its totient is φ = 205948.

The previous prime is 205937. The next prime is 205951. The reversal of 205949 is 949502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 145924 + 60025 = 382^2 + 245^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-205949 is a prime.

Together with 205951, it forms a pair of twin primes.

It is a Chen prime.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (205549) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102974 + 102975.

It is an arithmetic number, because the mean of its divisors is an integer number (102975).

2²⁰⁵⁹⁴⁹ is an apocalyptic number.

It is an amenable number.

205949 is a deficient number, since it is larger than the sum of its proper divisors (1).

205949 is an equidigital number, since it uses as much as digits as its factorization.

205949 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3240, while the sum is 29.

The square root of 205949 is about 453.8160420258. The cubic root of 205949 is about 59.0545315995.

The spelling of 205949 in words is "two hundred five thousand, nine hundred forty-nine".