21020000220 has 72 divisors (see below), whose sum is σ = 63791778960. Its totient is φ = 5602598400.

The previous prime is 21020000207. The next prime is 21020000237. The reversal of 21020000220 is 2200002012.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 355795 + ... + 410645.

It is an arithmetic number, because the mean of its divisors is an integer number (885996930).

Almost surely, 2^21020000220 is an apocalyptic number.

21020000220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21020000220 is an abundant number, since it is smaller than the sum of its proper divisors (42771778740).

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

21020000220 is a wasteful number, since it uses less digits than its factorization.

21020000220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56995 (or 56990 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 9.

Adding to 21020000220 its reverse (2200002012), we get a palindrome (23220002232).

The spelling of 21020000220 in words is "twenty-one billion, twenty million, two hundred twenty", and thus it is an aban number.