243281 has 4 divisors (see below), whose sum is σ = 251700. Its totient is φ = 234864.

The previous prime is 243263. The next prime is 243301. The reversal of 243281 is 182342.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 173056 + 70225 = 416^2 + 265^2 .

It is a cyclic number.

It is not a de Polignac number, because 243281 - 2¹⁰ = 242257 is a prime.

It is a super-2 number, since 2×243281² = 118371289922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (243781) 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, 4166 + ... + 4223.

It is an arithmetic number, because the mean of its divisors is an integer number (62925).

2²⁴³²⁸¹ is an apocalyptic number.

It is an amenable number.

243281 is a deficient number, since it is larger than the sum of its proper divisors (8419).

243281 is an equidigital number, since it uses as much as digits as its factorization.

243281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8418.

The product of its digits is 384, while the sum is 20.

The square root of 243281 is about 493.2352379950. The cubic root of 243281 is about 62.4265590700.

The spelling of 243281 in words is "two hundred forty-three thousand, two hundred eighty-one".