21211111212 has 96 divisors (see below), whose sum is σ = 52882502400. Its totient is φ = 6604238592.

The previous prime is 21211111147. The next prime is 21211111253.

It is a happy number.

21211111212 is nontrivially palindromic in base 10.

It is a super-4 number, since 4×21211111212⁴ (a number of 42 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 21211111191 and 21211111200.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 2300203 + ... + 2309405.

It is an arithmetic number, because the mean of its divisors is an integer number (550859400).

Almost surely, 2^21211111212 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 21211111212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26441251200).

21211111212 is an abundant number, since it is smaller than the sum of its proper divisors (31671391188).

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

21211111212 is a wasteful number, since it uses less digits than its factorization.

21211111212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9455 (or 9453 counting only the distinct ones).

The product of its digits is 16, while the sum is 15.

The spelling of 21211111212 in words is "twenty-one billion, two hundred eleven million, one hundred eleven thousand, two hundred twelve".