213523021 has 4 divisors (see below), whose sum is σ = 218066112. Its totient is φ = 208979932.

The previous prime is 213522943. The next prime is 213523033. The reversal of 213523021 is 120325312.

213523021 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 213523021 - 2¹⁵ = 213490253 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 213523021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213523081) 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, 2271475 + ... + 2271568.

It is an arithmetic number, because the mean of its divisors is an integer number (54516528).

Almost surely, 2^213523021 is an apocalyptic number.

It is an amenable number.

213523021 is a deficient number, since it is larger than the sum of its proper divisors (4543091).

213523021 is an equidigital number, since it uses as much as digits as its factorization.

213523021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4543090.

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

The square root of 213523021 is about 14612.4269373708. The cubic root of 213523021 is about 597.6976777462.

Adding to 213523021 its reverse (120325312), we get a palindrome (333848333).

The spelling of 213523021 in words is "two hundred thirteen million, five hundred twenty-three thousand, twenty-one".