243540 has 96 divisors (see below), whose sum is σ = 846720. Its totient is φ = 57600.

The previous prime is 243539. The next prime is 243553. The reversal of 243540 is 45342.

It is a happy number.

It is a super-3 number, since 3×243540³ = 43334337341592000, which contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5920 + ... + 5960.

It is an arithmetic number, because the mean of its divisors is an integer number (8820).

2²⁴³⁵⁴⁰ is an apocalyptic number.

243540 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 243540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (423360).

243540 is an abundant number, since it is smaller than the sum of its proper divisors (603180).

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

243540 is a wasteful number, since it uses less digits than its factorization.

243540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70 (or 62 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 18.

The square root of 243540 is about 493.4977203595. The cubic root of 243540 is about 62.4487045787.

243540 divided by its sum of digits (18) gives a triangular number (13530 = T₁₆₄).

Adding to 243540 its reverse (45342), we get a palindrome (288882).

The spelling of 243540 in words is "two hundred forty-three thousand, five hundred forty".