213230021 has 4 divisors (see below), whose sum is σ = 214588332. Its totient is φ = 211871712.

The previous prime is 213230009. The next prime is 213230041. The reversal of 213230021 is 120032312.

It is a happy number.

213230021 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.

It can be written as a sum of positive squares in 2 ways, for example, as 116424100 + 96805921 = 10790^2 + 9839^2 .

It is a cyclic number.

It is not a de Polignac number, because 213230021 - 2⁶ = 213229957 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 213229978 and 213230005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213230041) 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, 678920 + ... + 679233.

It is an arithmetic number, because the mean of its divisors is an integer number (53647083).

Almost surely, 2^213230021 is an apocalyptic number.

It is an amenable number.

213230021 is a deficient number, since it is larger than the sum of its proper divisors (1358311).

213230021 is a wasteful number, since it uses less digits than its factorization.

213230021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1358310.

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 213230021 is about 14602.3977825561. The cubic root of 213230021 is about 597.4241622204.

Adding to 213230021 its reverse (120032312), we get a palindrome (333262333).

The spelling of 213230021 in words is "two hundred thirteen million, two hundred thirty thousand, twenty-one".