213404521 has 4 divisors (see below), whose sum is σ = 232804944. Its totient is φ = 194004100.

The previous prime is 213404501. The next prime is 213404531. The reversal of 213404521 is 125404312.

213404521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 213404521 - 2¹⁹ = 212880233 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 213404492 and 213404501.

It is not an unprimeable number, because it can be changed into a prime (213404501) 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, 9700195 + ... + 9700216.

It is an arithmetic number, because the mean of its divisors is an integer number (58201236).

Almost surely, 2^213404521 is an apocalyptic number.

It is an amenable number.

213404521 is a deficient number, since it is larger than the sum of its proper divisors (19400423).

213404521 is a wasteful number, since it uses less digits than its factorization.

213404521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19400422.

The product of its (nonzero) digits is 960, while the sum is 22.

The square root of 213404521 is about 14608.3716067192. The cubic root of 213404521 is about 597.5870881387.

Adding to 213404521 its reverse (125404312), we get a palindrome (338808833).

The spelling of 213404521 in words is "two hundred thirteen million, four hundred four thousand, five hundred twenty-one".