21212110220 has 96 divisors (see below), whose sum is σ = 53336371200. Its totient is φ = 6932977920.

The previous prime is 21212110187. The next prime is 21212110229. The reversal of 21212110220 is 2201121212.

It is a super-3 number, since 3×21212110220³ (a number of 32 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (14).

It is a junction number, because it is equal to n+sod(n) for n = 21212110195 and 21212110204.

It is not an unprimeable number, because it can be changed into a prime (21212110229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 254306 + ... + 327254.

It is an arithmetic number, because the mean of its divisors is an integer number (555587200).

Almost surely, 2^21212110220 is an apocalyptic number.

21212110220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21212110220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26668185600).

21212110220 is an abundant number, since it is smaller than the sum of its proper divisors (32124260980).

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

21212110220 is a wasteful number, since it uses less digits than its factorization.

21212110220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73063 (or 73061 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21212110220 its reverse (2201121212), we get a palindrome (23413231432).

The spelling of 21212110220 in words is "twenty-one billion, two hundred twelve million, one hundred ten thousand, two hundred twenty".