213120123121 has 4 divisors (see below), whose sum is σ = 213514061044. Its totient is φ = 212726185200.

The previous prime is 213120123113. The next prime is 213120123131. The reversal of 213120123121 is 121321021312.

213120123121 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 39397883121 + 173722240000 = 198489^2 + 416800^2 .

It is a cyclic number.

It is not a de Polignac number, because 213120123121 - 2³ = 213120123113 is a prime.

It is a super-2 number, since 2×213120123121² (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 (213120123101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 196968150 + ... + 196969231.

It is an arithmetic number, because the mean of its divisors is an integer number (53378515261).

Almost surely, 2^213120123121 is an apocalyptic number.

It is an amenable number.

213120123121 is a deficient number, since it is larger than the sum of its proper divisors (393937923).

213120123121 is an equidigital number, since it uses as much as digits as its factorization.

213120123121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 393937922.

The product of its (nonzero) digits is 144, while the sum is 19.

Adding to 213120123121 its reverse (121321021312), we get a palindrome (334441144433).

The spelling of 213120123121 in words is "two hundred thirteen billion, one hundred twenty million, one hundred twenty-three thousand, one hundred twenty-one".