21220012212 has 96 divisors (see below), whose sum is σ = 59931110400. Its totient is φ = 5708454912.

The previous prime is 21220012207. The next prime is 21220012223. The reversal of 21220012212 is 21221002212.

It is a junction number, because it is equal to n+sod(n) for n = 21220012191 and 21220012200.

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, 219364 + ... + 300932.

It is an arithmetic number, because the mean of its divisors is an integer number (624282400).

Almost surely, 2^21220012212 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 21220012212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29965555200).

21220012212 is an abundant number, since it is smaller than the sum of its proper divisors (38711098188).

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

21220012212 is a wasteful number, since it uses less digits than its factorization.

21220012212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81765 (or 81763 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 21220012212 its reverse (21221002212), we get a palindrome (42441014424).

The spelling of 21220012212 in words is "twenty-one billion, two hundred twenty million, twelve thousand, two hundred twelve".