243440 has 40 divisors (see below), whose sum is σ = 602640. Its totient is φ = 91136.

The previous prime is 243437. The next prime is 243461. The reversal of 243440 is 44342.

243440 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

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 (17).

It is a plaindrome in base 11.

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 7 ways as a sum of consecutive naturals, for example, 1271 + ... + 1449.

It is an arithmetic number, because the mean of its divisors is an integer number (15066).

2²⁴³⁴⁴⁰ is an apocalyptic number.

243440 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 243440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (301320).

243440 is an abundant number, since it is smaller than the sum of its proper divisors (359200).

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

243440 is a wasteful number, since it uses less digits than its factorization.

243440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 209 (or 203 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 17.

The square root of 243440 is about 493.3963923662. The cubic root of 243440 is about 62.4401560508.

Adding to 243440 its reverse (44342), we get a palindrome (287782).

The spelling of 243440 in words is "two hundred forty-three thousand, four hundred forty", and thus it is an iban number.