320213521 has 4 divisors (see below), whose sum is σ = 334135872. Its totient is φ = 306291172.

The previous prime is 320213497. The next prime is 320213527. The reversal of 320213521 is 125312023.

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, and also an emirpimes, since its reverse is a distinct semiprime: 125312023 = 677 ⋅185099.

It is a cyclic number.

It is not a de Polignac number, because 320213521 - 2¹³ = 320205329 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (320213527) 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, 6961141 + ... + 6961186.

It is an arithmetic number, because the mean of its divisors is an integer number (83533968).

Almost surely, 2^320213521 is an apocalyptic number.

It is an amenable number.

320213521 is a deficient number, since it is larger than the sum of its proper divisors (13922351).

320213521 is a wasteful number, since it uses less digits than its factorization.

320213521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13922350.

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

The square root of 320213521 is about 17894.5109181559. The cubic root of 320213521 is about 684.1424764190.

Adding to 320213521 its reverse (125312023), we get a palindrome (445525544).

The spelling of 320213521 in words is "three hundred twenty million, two hundred thirteen thousand, five hundred twenty-one".