213131212121 has 16 divisors (see below), whose sum is σ = 222381490176. Its totient is φ = 204033000000.

The previous prime is 213131212111. The next prime is 213131212139. The reversal of 213131212121 is 121212131312.

It is a cyclic number.

It is not a de Polignac number, because 213131212121 - 2²⁶ = 213064103257 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 213131212093 and 213131212102.

It is not an unprimeable number, because it can be changed into a prime (213131212111) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3574211 + ... + 3633351.

It is an arithmetic number, because the mean of its divisors is an integer number (13898843136).

Almost surely, 2^213131212121 is an apocalyptic number.

It is an amenable number.

213131212121 is a deficient number, since it is larger than the sum of its proper divisors (9250278055).

213131212121 is a wasteful number, since it uses less digits than its factorization.

213131212121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60424.

The product of its digits is 144, while the sum is 20.

Adding to 213131212121 its reverse (121212131312), we get a palindrome (334343343433).

The spelling of 213131212121 in words is "two hundred thirteen billion, one hundred thirty-one million, two hundred twelve thousand, one hundred twenty-one".