243123213 has 4 divisors (see below), whose sum is σ = 324164288. Its totient is φ = 162082140.

The previous prime is 243123193. The next prime is 243123217. The reversal of 243123213 is 312321342.

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 243123213 - 2⁶ = 243123149 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 243123213.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243123217) 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, 40520533 + ... + 40520538.

It is an arithmetic number, because the mean of its divisors is an integer number (81041072).

Almost surely, 2^243123213 is an apocalyptic number.

It is an amenable number.

243123213 is a deficient number, since it is larger than the sum of its proper divisors (81041075).

243123213 is an equidigital number, since it uses as much as digits as its factorization.

243123213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81041074.

The product of its digits is 864, while the sum is 21.

The square root of 243123213 is about 15592.4088260923. The cubic root of 243123213 is about 624.1305996162.

Adding to 243123213 its reverse (312321342), we get a palindrome (555444555).

The spelling of 243123213 in words is "two hundred forty-three million, one hundred twenty-three thousand, two hundred thirteen".