205040 has 40 divisors (see below), whose sum is σ = 522288. Its totient is φ = 74240.

The previous prime is 205033. The next prime is 205043. The reversal of 205040 is 40502.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (11).

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205043) 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, 764 + ... + 996.

2²⁰⁵⁰⁴⁰ is an apocalyptic number.

205040 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 205040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (261144).

205040 is an abundant number, since it is smaller than the sum of its proper divisors (317248).

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

205040 is a wasteful number, since it uses less digits than its factorization.

205040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 257 (or 251 counting only the distinct ones).

The product of its (nonzero) digits is 40, while the sum is 11.

The square root of 205040 is about 452.8134273627. The cubic root of 205040 is about 58.9675201867.

Adding to 205040 its reverse (40502), we get a palindrome (245542).

The spelling of 205040 in words is "two hundred five thousand, forty".