243403221 has 4 divisors (see below), whose sum is σ = 324537632. Its totient is φ = 162268812.

The previous prime is 243403211. The next prime is 243403241. The reversal of 243403221 is 122304342.

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 243403221 - 2¹¹ = 243401173 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 (243403211) 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, 40567201 + ... + 40567206.

It is an arithmetic number, because the mean of its divisors is an integer number (81134408).

Almost surely, 2^243403221 is an apocalyptic number.

It is an amenable number.

243403221 is a deficient number, since it is larger than the sum of its proper divisors (81134411).

243403221 is an equidigital number, since it uses as much as digits as its factorization.

243403221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81134410.

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

The square root of 243403221 is about 15601.3852269598. The cubic root of 243403221 is about 624.3701139897.

Adding to 243403221 its reverse (122304342), we get a palindrome (365707563).

The spelling of 243403221 in words is "two hundred forty-three million, four hundred three thousand, two hundred twenty-one".