21221104320 has 336 divisors, whose sum is σ = 80736277440. Its totient is φ = 5082144768.

The previous prime is 21221104309. The next prime is 21221104321. The reversal of 21221104320 is 2340112212.

It is a happy number.

21221104320 is a `hidden beast` number, since 2 + 1 + 221 + 10 + 432 + 0 = 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 = 21221104293 and 21221104302.

It is not an unprimeable number, because it can be changed into a prime (21221104321) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1377621 + ... + 1392939.

It is an arithmetic number, because the mean of its divisors is an integer number (240286540).

Almost surely, 2^21221104320 is an apocalyptic number.

21221104320 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 21221104320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40368138720).

21221104320 is an abundant number, since it is smaller than the sum of its proper divisors (59515173120).

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

21221104320 is a wasteful number, since it uses less digits than its factorization.

21221104320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15392 (or 15379 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

Adding to 21221104320 its reverse (2340112212), we get a palindrome (23561216532).

The spelling of 21221104320 in words is "twenty-one billion, two hundred twenty-one million, one hundred four thousand, three hundred twenty".