21220220220 has 24 divisors (see below), whose sum is σ = 59416616784. Its totient is φ = 5658725376.

The previous prime is 21220220173. The next prime is 21220220237. The reversal of 21220220220 is 2202202212.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21220220220.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 176835109 + ... + 176835228.

It is an arithmetic number, because the mean of its divisors is an integer number (2475692366).

Almost surely, 2^21220220220 is an apocalyptic number.

21220220220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21220220220 is an abundant number, since it is smaller than the sum of its proper divisors (38196396564).

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

21220220220 is a wasteful number, since it uses less digits than its factorization.

21220220220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 353670349 (or 353670347 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 15.

Adding to 21220220220 its reverse (2202202212), we get a palindrome (23422422432).

The spelling of 21220220220 in words is "twenty-one billion, two hundred twenty million, two hundred twenty thousand, two hundred twenty".