21210352212 has 96 divisors (see below), whose sum is σ = 57560315904. Its totient is φ = 5953276800.

The previous prime is 21210352211. The next prime is 21210352223. The reversal of 21210352212 is 21225301212.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210352211) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5034787 + ... + 5038997.

It is an arithmetic number, because the mean of its divisors is an integer number (599586624).

Almost surely, 2^21210352212 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 21210352212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28780157952).

21210352212 is an abundant number, since it is smaller than the sum of its proper divisors (36349963692).

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

21210352212 is a wasteful number, since it uses less digits than its factorization.

21210352212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5269 (or 5267 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 21.

Adding to 21210352212 its reverse (21225301212), we get a palindrome (42435653424).

The spelling of 21210352212 in words is "twenty-one billion, two hundred ten million, three hundred fifty-two thousand, two hundred twelve".