21210202220 has 24 divisors (see below), whose sum is σ = 44814691824. Its totient is φ = 8432030016.

The previous prime is 21210202219. The next prime is 21210202229. The reversal of 21210202220 is 2220201212.

It is a junction number, because it is equal to n+sod(n) for n = 21210202195 and 21210202204.

It is not an unprimeable number, because it can be changed into a prime (21210202229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3249839 + ... + 3256358.

It is an arithmetic number, because the mean of its divisors is an integer number (1867278826).

Almost surely, 2^21210202220 is an apocalyptic number.

21210202220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21210202220 is an abundant number, since it is smaller than the sum of its proper divisors (23604489604).

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

21210202220 is a wasteful number, since it uses less digits than its factorization.

21210202220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6506369 (or 6506367 counting only the distinct ones).

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

Adding to 21210202220 its reverse (2220201212), we get a palindrome (23430403432).

The spelling of 21210202220 in words is "twenty-one billion, two hundred ten million, two hundred two thousand, two hundred twenty".