21211010220 has 96 divisors (see below), whose sum is σ = 61241225472. Its totient is φ = 5482617088.

The previous prime is 21211010207. The next prime is 21211010243. The reversal of 21211010220 is 2201011212.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 21211010196 and 21211010205.

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, 223759 + ... + 304121.

It is an arithmetic number, because the mean of its divisors is an integer number (637929432).

Almost surely, 2^21211010220 is an apocalyptic number.

21211010220 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 21211010220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30620612736).

21211010220 is an abundant number, since it is smaller than the sum of its proper divisors (40030215252).

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

21211010220 is a wasteful number, since it uses less digits than its factorization.

21211010220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80511 (or 80509 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21211010220 its reverse (2201011212), we get a palindrome (23412021432).

The spelling of 21211010220 in words is "twenty-one billion, two hundred eleven million, ten thousand, two hundred twenty".