213340021 has 4 divisors (see below), whose sum is σ = 225889452. Its totient is φ = 200790592.

The previous prime is 213339989. The next prime is 213340027. The reversal of 213340021 is 120043312.

It is a happy number.

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 175271121 + 38068900 = 13239^2 + 6170^2 .

It is a cyclic number.

It is not a de Polignac number, because 213340021 - 2⁵ = 213339989 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 213339977 and 213340004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213340027) 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, 6274690 + ... + 6274723.

It is an arithmetic number, because the mean of its divisors is an integer number (56472363).

Almost surely, 2^213340021 is an apocalyptic number.

It is an amenable number.

213340021 is a deficient number, since it is larger than the sum of its proper divisors (12549431).

213340021 is a wasteful number, since it uses less digits than its factorization.

213340021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12549430.

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 213340021 is about 14606.1638016284. The cubic root of 213340021 is about 597.5268765885.

Adding to 213340021 its reverse (120043312), we get a palindrome (333383333).

The spelling of 213340021 in words is "two hundred thirteen million, three hundred forty thousand, twenty-one".