205540 has 24 divisors (see below), whose sum is σ = 443520. Its totient is φ = 79968.

The previous prime is 205537. The next prime is 205549. The reversal of 205540 is 45502.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (205549) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 741 + ... + 979.

It is an arithmetic number, because the mean of its divisors is an integer number (18480).

2²⁰⁵⁵⁴⁰ is an apocalyptic number.

205540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 205540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (221760).

205540 is an abundant number, since it is smaller than the sum of its proper divisors (237980).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

205540 is a wasteful number, since it uses less digits than its factorization.

205540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 291 (or 289 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 16.

The square root of 205540 is about 453.3651949588. The cubic root of 205540 is about 59.0154129990.

The spelling of 205540 in words is "two hundred five thousand, five hundred forty".