205445 has 8 divisors (see below), whose sum is σ = 261144. Its totient is φ = 154624.

The previous prime is 205441. The next prime is 205453. The reversal of 205445 is 544502.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 101761 + 103684 = 319^2 + 322^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 205445 - 2² = 205441 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1124 + ... + 1293.

It is an arithmetic number, because the mean of its divisors is an integer number (32643).

2²⁰⁵⁴⁴⁵ is an apocalyptic number.

It is an amenable number.

205445 is a deficient number, since it is larger than the sum of its proper divisors (55699).

205445 is a wasteful number, since it uses less digits than its factorization.

205445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2439.

The product of its (nonzero) digits is 800, while the sum is 20.

The square root of 205445 is about 453.2604108016. The cubic root of 205445 is about 59.0063193461.

Adding to 205445 its reverse (544502), we get a palindrome (749947).

It can be divided in two parts, 20 and 5445, that multiplied together give a square (108900 = 330²).

The spelling of 205445 in words is "two hundred five thousand, four hundred forty-five".