231243213 has 4 divisors (see below), whose sum is σ = 308324288. Its totient is φ = 154162140.

The previous prime is 231243211. The next prime is 231243223. The reversal of 231243213 is 312342132.

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 231243213 - 2¹ = 231243211 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 231243213.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231243211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 38540533 + ... + 38540538.

It is an arithmetic number, because the mean of its divisors is an integer number (77081072).

Almost surely, 2^231243213 is an apocalyptic number.

It is an amenable number.

231243213 is a deficient number, since it is larger than the sum of its proper divisors (77081075).

231243213 is an equidigital number, since it uses as much as digits as its factorization.

231243213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77081074.

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

The square root of 231243213 is about 15206.6831689228. The cubic root of 231243213 is about 613.7945081882.

Adding to 231243213 its reverse (312342132), we get a palindrome (543585345).

The spelling of 231243213 in words is "two hundred thirty-one million, two hundred forty-three thousand, two hundred thirteen".