213421204121 has 4 divisors (see below), whose sum is σ = 213451870644. Its totient is φ = 213390537600.

The previous prime is 213421204079. The next prime is 213421204127. The reversal of 213421204121 is 121402124312.

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 196081581721 + 17339622400 = 442811^2 + 131680^2 .

It is a cyclic number.

It is not a de Polignac number, because 213421204121 - 2⁶ = 213421204057 is a prime.

It is a super-2 number, since 2×213421204121² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (213421204127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15322820 + ... + 15336741.

It is an arithmetic number, because the mean of its divisors is an integer number (53362967661).

Almost surely, 2^213421204121 is an apocalyptic number.

It is an amenable number.

213421204121 is a deficient number, since it is larger than the sum of its proper divisors (30666523).

213421204121 is an equidigital number, since it uses as much as digits as its factorization.

213421204121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30666522.

The product of its (nonzero) digits is 768, while the sum is 23.

Adding to 213421204121 its reverse (121402124312), we get a palindrome (334823328433).

The spelling of 213421204121 in words is "two hundred thirteen billion, four hundred twenty-one million, two hundred four thousand, one hundred twenty-one".