21220223220 has 576 divisors, whose sum is σ = 78592550400. Its totient is φ = 4628736000.

The previous prime is 21220223203. The next prime is 21220223221. The reversal of 21220223220 is 2232202212.

21220223220 is a `hidden beast` number, since 2 + 1 + 220 + 223 + 220 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21220223193 and 21220223202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21220223221) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 210101170 + ... + 210101270.

It is an arithmetic number, because the mean of its divisors is an integer number (136445400).

Almost surely, 2^21220223220 is an apocalyptic number.

21220223220 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 21220223220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39296275200).

21220223220 is an abundant number, since it is smaller than the sum of its proper divisors (57372327180).

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

21220223220 is a wasteful number, since it uses less digits than its factorization.

21220223220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 261 (or 242 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

Adding to 21220223220 its reverse (2232202212), we get a palindrome (23452425432).

The spelling of 21220223220 in words is "twenty-one billion, two hundred twenty million, two hundred twenty-three thousand, two hundred twenty".