21210303220 has 24 divisors (see below), whose sum is σ = 44577930600. Its totient is φ = 8477208192.

The previous prime is 21210303217. The next prime is 21210303221. The reversal of 21210303220 is 2230301212.

It can be written as a sum of positive squares in 4 ways, for example, as 1821411684 + 19388891536 = 42678^2 + 139244^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21210303194 and 21210303203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210303221) 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, 406875 + ... + 456034.

It is an arithmetic number, because the mean of its divisors is an integer number (1857413775).

Almost surely, 2^21210303220 is an apocalyptic number.

21210303220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21210303220 is an abundant number, since it is smaller than the sum of its proper divisors (23367627380).

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

21210303220 is a wasteful number, since it uses less digits than its factorization.

21210303220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 864147 (or 864145 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 16.

Adding to 21210303220 its reverse (2230301212), we get a palindrome (23440604432).

The spelling of 21210303220 in words is "twenty-one billion, two hundred ten million, three hundred three thousand, two hundred twenty".