243343021 has 4 divisors (see below), whose sum is σ = 244032732. Its totient is φ = 242653312.

The previous prime is 243343019. The next prime is 243343069. The reversal of 243343021 is 120343342.

It is a happy number.

243343021 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.

It can be written as a sum of positive squares in 2 ways, for example, as 188375625 + 54967396 = 13725^2 + 7414^2 .

It is a cyclic number.

It is not a de Polignac number, because 243343021 - 2¹ = 243343019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 243342983 and 243343001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243340021) 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, 344326 + ... + 345031.

It is an arithmetic number, because the mean of its divisors is an integer number (61008183).

Almost surely, 2^243343021 is an apocalyptic number.

It is an amenable number.

243343021 is a deficient number, since it is larger than the sum of its proper divisors (689711).

243343021 is an equidigital number, since it uses as much as digits as its factorization.

243343021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 689710.

The product of its (nonzero) digits is 1728, while the sum is 22.

The square root of 243343021 is about 15599.4557917897. The cubic root of 243343021 is about 624.3186353775.

Adding to 243343021 its reverse (120343342), we get a palindrome (363686363).

It can be divided in two parts, 2433 and 43021, that added together give a palindrome (45454).

The spelling of 243343021 in words is "two hundred forty-three million, three hundred forty-three thousand, twenty-one".