521231213 has 4 divisors (see below), whose sum is σ = 521336160. Its totient is φ = 521126268.

The previous prime is 521231197. The next prime is 521231233. The reversal of 521231213 is 312132125.

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 a cyclic number.

It is not a de Polignac number, because 521231213 - 2⁴ = 521231197 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521231233) 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, 44633 + ... + 55086.

It is an arithmetic number, because the mean of its divisors is an integer number (130334040).

Almost surely, 2^521231213 is an apocalyptic number.

It is an amenable number.

521231213 is a deficient number, since it is larger than the sum of its proper divisors (104947).

521231213 is an equidigital number, since it uses as much as digits as its factorization.

521231213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104946.

The product of its digits is 360, while the sum is 20.

The square root of 521231213 is about 22830.4886719492. The cubic root of 521231213 is about 804.7793142728.

Adding to 521231213 its reverse (312132125), we get a palindrome (833363338).

The spelling of 521231213 in words is "five hundred twenty-one million, two hundred thirty-one thousand, two hundred thirteen".