213231123121 has 4 divisors (see below), whose sum is σ = 220583920500. Its totient is φ = 205878325744.

The previous prime is 213231123113. The next prime is 213231123169. The reversal of 213231123121 is 121321132312.

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 158634127521 + 54596995600 = 398289^2 + 233660^2 .

It is a cyclic number.

It is not a de Polignac number, because 213231123121 - 2³ = 213231123113 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 213231123092 and 213231123101.

It is not an unprimeable number, because it can be changed into a prime (213231123101) 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, 3676398646 + ... + 3676398703.

It is an arithmetic number, because the mean of its divisors is an integer number (55145980125).

Almost surely, 2^213231123121 is an apocalyptic number.

It is an amenable number.

213231123121 is a deficient number, since it is larger than the sum of its proper divisors (7352797379).

213231123121 is an equidigital number, since it uses as much as digits as its factorization.

213231123121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7352797378.

The product of its digits is 432, while the sum is 22.

Adding to 213231123121 its reverse (121321132312), we get a palindrome (334552255433).

The spelling of 213231123121 in words is "two hundred thirteen billion, two hundred thirty-one million, one hundred twenty-three thousand, one hundred twenty-one".