212121312 has 96 divisors (see below), whose sum is σ = 620434080. Its totient is φ = 63006720.

The previous prime is 212121289. The next prime is 212121319. The reversal of 212121312 is 213121212.

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-4 number, since 4×212121312⁴ (a number of 34 digits) contains 4444 as substring.

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 212121291 and 212121300.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212121319) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 33262 + ... + 39122.

It is an arithmetic number, because the mean of its divisors is an integer number (6462855).

Almost surely, 2^212121312 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 212121312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (310217040).

212121312 is an abundant number, since it is smaller than the sum of its proper divisors (408312768).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

212121312 is a wasteful number, since it uses less digits than its factorization.

212121312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5916 (or 5908 counting only the distinct ones).

The product of its digits is 48, while the sum is 15.

The square root of 212121312 is about 14564.3850539595. The cubic root of 212121312 is about 596.3869085117.

Adding to 212121312 its reverse (213121212), we get a palindrome (425242524).

The spelling of 212121312 in words is "two hundred twelve million, one hundred twenty-one thousand, three hundred twelve".