212112121 has 4 divisors (see below), whose sum is σ = 228428452. Its totient is φ = 195795792.

The previous prime is 212112091. The next prime is 212112161. The reversal of 212112121 is 121211212.

212112121 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 30913600 + 181198521 = 5560^2 + 13461^2 .

It is a cyclic number.

It is not a de Polignac number, because 212112121 - 2⁷ = 212111993 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13), and also a Moran number because the ratio is a prime number: 16316317 = 212112121 / (2 + 1 + 2 + 1 + 1 + 2 + 1 + 2 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (212112161) 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, 8158146 + ... + 8158171.

It is an arithmetic number, because the mean of its divisors is an integer number (57107113).

Almost surely, 2^212112121 is an apocalyptic number.

It is an amenable number.

212112121 is a deficient number, since it is larger than the sum of its proper divisors (16316331).

212112121 is a wasteful number, since it uses less digits than its factorization.

212112121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16316330.

The product of its digits is 16, while the sum is 13.

The square root of 212112121 is about 14564.0695205701. The cubic root of 212112121 is about 596.3782947753.

Adding to 212112121 its reverse (121211212), we get a palindrome (333323333).

Subtracting from 212112121 its reverse (121211212), we obtain a palindrome (90900909).

It can be divided in two parts, 21211 and 2121, that added together give a palindrome (23332).

The spelling of 212112121 in words is "two hundred twelve million, one hundred twelve thousand, one hundred twenty-one".