213320521 has 4 divisors (see below), whose sum is σ = 215277700. Its totient is φ = 211363344.

The previous prime is 213320509. The next prime is 213320567. The reversal of 213320521 is 125023312.

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 111007296 + 102313225 = 10536^2 + 10115^2 .

It is a cyclic number.

It is not a de Polignac number, because 213320521 - 2¹¹ = 213318473 is a prime.

It is a super-2 number, since 2×213320521² = 91011289359422882, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (213320321) 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, 978426 + ... + 978643.

It is an arithmetic number, because the mean of its divisors is an integer number (53819425).

Almost surely, 2^213320521 is an apocalyptic number.

It is an amenable number.

213320521 is a deficient number, since it is larger than the sum of its proper divisors (1957179).

213320521 is a wasteful number, since it uses less digits than its factorization.

213320521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1957178.

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 213320521 is about 14605.4962599701. The cubic root of 213320521 is about 597.5086707074.

Adding to 213320521 its reverse (125023312), we get a palindrome (338343833).

The spelling of 213320521 in words is "two hundred thirteen million, three hundred twenty thousand, five hundred twenty-one".