243561 has 8 divisors (see below), whose sum is σ = 341920. Its totient is φ = 153792.

The previous prime is 243553. The next prime is 243577. The reversal of 243561 is 165342.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 243561 - 2³ = 243553 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 243561.

It is not an unprimeable number, because it can be changed into a prime (243521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2080 + ... + 2193.

It is an arithmetic number, because the mean of its divisors is an integer number (42740).

2²⁴³⁵⁶¹ is an apocalyptic number.

It is an amenable number.

243561 is a deficient number, since it is larger than the sum of its proper divisors (98359).

243561 is a wasteful number, since it uses less digits than its factorization.

243561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4295.

The product of its digits is 720, while the sum is 21.

The square root of 243561 is about 493.5189965949. The cubic root of 243561 is about 62.4504994722.

The spelling of 243561 in words is "two hundred forty-three thousand, five hundred sixty-one".