21000212210220 has 24 divisors (see below), whose sum is σ = 58800594188784. Its totient is φ = 5600056589376.

The previous prime is 21000212210213. The next prime is 21000212210221. The reversal of 21000212210220 is 2201221200012.

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 21000212210220.

It is not an unprimeable number, because it can be changed into a prime (21000212210221) 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, 175001768359 + ... + 175001768478.

It is an arithmetic number, because the mean of its divisors is an integer number (2450024757866).

Almost surely, 2^{21000212210220} is an apocalyptic number.

21000212210220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21000212210220 is an abundant number, since it is smaller than the sum of its proper divisors (37800381978564).

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

21000212210220 is a wasteful number, since it uses less digits than its factorization.

21000212210220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 350003536849 (or 350003536847 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 21000212210220 its reverse (2201221200012), we get a palindrome (23201433410232).

The spelling of 21000212210220 in words is "twenty-one trillion, two hundred twelve million, two hundred ten thousand, two hundred twenty".