21100202220 has 72 divisors (see below), whose sum is σ = 61188223824. Its totient is φ = 5432682752.

The previous prime is 21100202177. The next prime is 21100202257. The reversal of 21100202220 is 2220200112.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 21100202196 and 21100202205.

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, 158619 + ... + 259538.

It is an arithmetic number, because the mean of its divisors is an integer number (849836442).

Almost surely, 2^21100202220 is an apocalyptic number.

21100202220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21100202220 is an abundant number, since it is smaller than the sum of its proper divisors (40088021604).

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

21100202220 is a wasteful number, since it uses less digits than its factorization.

21100202220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 418227 (or 418196 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

Adding to 21100202220 its reverse (2220200112), we get a palindrome (23320402332).

The spelling of 21100202220 in words is "twenty-one billion, one hundred million, two hundred two thousand, two hundred twenty".