21203222220 has 144 divisors (see below), whose sum is σ = 66130017408. Its totient is φ = 5495109120.

The previous prime is 21203222191. The next prime is 21203222251. The reversal of 21203222220 is 2222230212.

21203222220 is a `hidden beast` number, since 2 + 120 + 322 + 2 + 220 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21203222193 and 21203222202.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 9902350 + ... + 9904490.

It is an arithmetic number, because the mean of its divisors is an integer number (459236232).

Almost surely, 2^21203222220 is an apocalyptic number.

21203222220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21203222220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33065008704).

21203222220 is an abundant number, since it is smaller than the sum of its proper divisors (44926795188).

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

21203222220 is a wasteful number, since it uses less digits than its factorization.

21203222220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3680 (or 3675 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

Adding to 21203222220 its reverse (2222230212), we get a palindrome (23425452432).

The spelling of 21203222220 in words is "twenty-one billion, two hundred three million, two hundred twenty-two thousand, two hundred twenty".