204540 has 48 divisors (see below), whose sum is σ = 655872. Its totient is φ = 46656.

The previous prime is 204521. The next prime is 204557. The reversal of 204540 is 45402.

204540 = 23² + 24² + ... + 85².

It is a super-2 number, since 2×204540² = 83673223200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is an unprimeable number.

204540 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 177 + ... + 663.

It is an arithmetic number, because the mean of its divisors is an integer number (13664).

2²⁰⁴⁵⁴⁰ is an apocalyptic number.

204540 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 204540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (327936).

204540 is an abundant number, since it is smaller than the sum of its proper divisors (451332).

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

204540 is a wasteful number, since it uses less digits than its factorization.

204540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 506 (or 504 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 15.

The square root of 204540 is about 452.2609865996. The cubic root of 204540 is about 58.9195494518.

Adding to 204540 its reverse (45402), we get a palindrome (249942).

It can be divided in two parts, 20 and 4540, that added together give a triangular number (4560 = T₉₅).

The spelling of 204540 in words is "two hundred four thousand, five hundred forty".