21021022220 has 96 divisors (see below), whose sum is σ = 48704495616. Its totient is φ = 7557580800.

The previous prime is 21021022207. The next prime is 21021022279. The reversal of 21021022220 is 2222012012.

It is a junction number, because it is equal to n+sod(n) for n = 21021022195 and 21021022204.

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, 9247004 + ... + 9249276.

It is an arithmetic number, because the mean of its divisors is an integer number (507338496).

Almost surely, 2^21021022220 is an apocalyptic number.

21021022220 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 21021022220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24352247808).

21021022220 is an abundant number, since it is smaller than the sum of its proper divisors (27683473396).

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

21021022220 is a wasteful number, since it uses less digits than its factorization.

21021022220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2751 (or 2749 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

Adding to 21021022220 its reverse (2222012012), we get a palindrome (23243034232).

The spelling of 21021022220 in words is "twenty-one billion, twenty-one million, twenty-two thousand, two hundred twenty".