21112212212 has 96 divisors (see below), whose sum is σ = 48221607168. Its totient is φ = 7848658944.

The previous prime is 21112212169. The next prime is 21112212223. The reversal of 21112212212 is 21221221112.

It is a Harshad number since it is a multiple of its sum of digits (17).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4682063 + ... + 4686569.

It is an arithmetic number, because the mean of its divisors is an integer number (502308408).

Almost surely, 2^21112212212 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 21112212212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24110803584).

21112212212 is an abundant number, since it is smaller than the sum of its proper divisors (27109394956).

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

21112212212 is a wasteful number, since it uses less digits than its factorization.

21112212212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5305 (or 5303 counting only the distinct ones).

The product of its digits is 64, while the sum is 17.

Adding to 21112212212 its reverse (21221221112), we get a palindrome (42333433324).

The spelling of 21112212212 in words is "twenty-one billion, one hundred twelve million, two hundred twelve thousand, two hundred twelve".