243640 has 16 divisors (see below), whose sum is σ = 548280. Its totient is φ = 97440.

The previous prime is 243631. The next prime is 243643. The reversal of 243640 is 46342.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243643) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3006 + ... + 3085.

2²⁴³⁶⁴⁰ is an apocalyptic number.

243640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

243640 is an abundant number, since it is smaller than the sum of its proper divisors (304640).

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

243640 is a wasteful number, since it uses less digits than its factorization.

243640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6102 (or 6098 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 19.

The square root of 243640 is about 493.5990275517. The cubic root of 243640 is about 62.4572507667.

Adding to 243640 its reverse (46342), we get a palindrome (289982).

The spelling of 243640 in words is "two hundred forty-three thousand, six hundred forty".