243340221 has 4 divisors (see below), whose sum is σ = 324453632. Its totient is φ = 162226812.

The previous prime is 243340213. The next prime is 243340267. The reversal of 243340221 is 122043342.

243340221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 243340221 - 2³ = 243340213 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243340271) 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, 40556701 + ... + 40556706.

It is an arithmetic number, because the mean of its divisors is an integer number (81113408).

Almost surely, 2^243340221 is an apocalyptic number.

It is an amenable number.

243340221 is a deficient number, since it is larger than the sum of its proper divisors (81113411).

243340221 is an equidigital number, since it uses as much as digits as its factorization.

243340221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81113410.

The product of its (nonzero) digits is 1152, while the sum is 21.

The square root of 243340221 is about 15599.3660448109. The cubic root of 243340221 is about 624.3162408169.

Adding to 243340221 its reverse (122043342), we get a palindrome (365383563).

The spelling of 243340221 in words is "two hundred forty-three million, three hundred forty thousand, two hundred twenty-one".