21201022212 has 12 divisors (see below), whose sum is σ = 49469051856. Its totient is φ = 7067007400.

The previous prime is 21201022147. The next prime is 21201022229. The reversal of 21201022212 is 21222010212.

It is a tau number, because it is divible by the number of its divisors (12).

It is a junction number, because it is equal to n+sod(n) for n = 21201022191 and 21201022200.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 883375914 + ... + 883375937.

It is an arithmetic number, because the mean of its divisors is an integer number (4122420988).

Almost surely, 2^21201022212 is an apocalyptic number.

It is an amenable number.

21201022212 is an abundant number, since it is smaller than the sum of its proper divisors (28268029644).

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

21201022212 is a wasteful number, since it uses less digits than its factorization.

21201022212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1766751858 (or 1766751856 counting only the distinct ones).

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

Adding to 21201022212 its reverse (21222010212), we get a palindrome (42423032424).

The spelling of 21201022212 in words is "twenty-one billion, two hundred one million, twenty-two thousand, two hundred twelve".