21212112012 has 192 divisors, whose sum is σ = 64265671680. Its totient is φ = 5288177664.

The previous prime is 21212112007. The next prime is 21212112023. The reversal of 21212112012 is 21021121212.

It is a super-3 number, since 3×21212112012³ (a number of 32 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21212111982 and 21212112000.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 12800688 + ... + 12802344.

It is an arithmetic number, because the mean of its divisors is an integer number (334717040).

Almost surely, 2^21212112012 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 21212112012, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32132835840).

21212112012 is an abundant number, since it is smaller than the sum of its proper divisors (43053559668).

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

21212112012 is a wasteful number, since it uses less digits than its factorization.

21212112012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2320 (or 2318 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21212112012 its reverse (21021121212), we get a palindrome (42233233224).

It can be divided in two parts, 212121 and 12012, that multiplied together give a palindrome (2547997452).

The spelling of 21212112012 in words is "twenty-one billion, two hundred twelve million, one hundred twelve thousand, twelve".