243440321 has 2 divisors, whose sum is σ = 243440322. Its totient is φ = 243440320.

The previous prime is 243440311. The next prime is 243440333. The reversal of 243440321 is 123044342.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 242736400 + 703921 = 15580^2 + 839^2 .

It is a cyclic number.

It is not a de Polignac number, because 243440321 - 2²² = 239246017 is a prime.

It is not a weakly prime, because it can be changed into another prime (243440311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121720160 + 121720161.

It is an arithmetic number, because the mean of its divisors is an integer number (121720161).

Almost surely, 2^243440321 is an apocalyptic number.

It is an amenable number.

243440321 is a deficient number, since it is larger than the sum of its proper divisors (1).

243440321 is an equidigital number, since it uses as much as digits as its factorization.

243440321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2304, while the sum is 23.

The square root of 243440321 is about 15602.5741786412. The cubic root of 243440321 is about 624.4018349537.

Adding to 243440321 its reverse (123044342), we get a palindrome (366484663).

The spelling of 243440321 in words is "two hundred forty-three million, four hundred forty thousand, three hundred twenty-one".