21220020220 has 144 divisors (see below), whose sum is σ = 53354790720. Its totient is φ = 6941915136.

The previous prime is 21220020187. The next prime is 21220020223. The reversal of 21220020220 is 2202002212.

It is a self number, because there is not a number n which added to its sum of digits gives 21220020220.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21220020223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 10156936 + ... + 10159024.

It is an arithmetic number, because the mean of its divisors is an integer number (370519380).

Almost surely, 2^21220020220 is an apocalyptic number.

21220020220 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 21220020220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26677395360).

21220020220 is an abundant number, since it is smaller than the sum of its proper divisors (32134770500).

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

21220020220 is a wasteful number, since it uses less digits than its factorization.

21220020220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2232 (or 2193 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 13.

Adding to 21220020220 its reverse (2202002212), we get a palindrome (23422022432).

The spelling of 21220020220 in words is "twenty-one billion, two hundred twenty million, twenty thousand, two hundred twenty".