213521521 has 4 divisors (see below), whose sum is σ = 220409344. Its totient is φ = 206633700.

The previous prime is 213521507. The next prime is 213521527. The reversal of 213521521 is 125125312.

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 213521521 - 2¹³ = 213513329 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 213521492 and 213521501.

It is not an unprimeable number, because it can be changed into a prime (213521527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3443865 + ... + 3443926.

It is an arithmetic number, because the mean of its divisors is an integer number (55102336).

Almost surely, 2^213521521 is an apocalyptic number.

It is an amenable number.

213521521 is a deficient number, since it is larger than the sum of its proper divisors (6887823).

213521521 is an equidigital number, since it uses as much as digits as its factorization.

213521521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6887822.

The product of its digits is 600, while the sum is 22.

The square root of 213521521 is about 14612.3756111044. The cubic root of 213521521 is about 597.6962781335.

Adding to 213521521 its reverse (125125312), we get a palindrome (338646833).

The spelling of 213521521 in words is "two hundred thirteen million, five hundred twenty-one thousand, five hundred twenty-one".