21021000220 has 24 divisors (see below), whose sum is σ = 48157201008. Its totient is φ = 7644000000.

The previous prime is 21021000199. The next prime is 21021000223. The reversal of 21021000220 is 2200012012.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 21021000197 and 21021000206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021000223) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47774781 + ... + 47775220.

It is an arithmetic number, because the mean of its divisors is an integer number (2006550042).

Almost surely, 2^21021000220 is an apocalyptic number.

21021000220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21021000220 is an abundant number, since it is smaller than the sum of its proper divisors (27136200788).

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

21021000220 is a wasteful number, since it uses less digits than its factorization.

21021000220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95550021 (or 95550019 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

Adding to 21021000220 its reverse (2200012012), we get a palindrome (23221012232).

The spelling of 21021000220 in words is "twenty-one billion, twenty-one million, two hundred twenty", and thus it is an aban number.