21221333320 has 96 divisors (see below), whose sum is σ = 55245859200. Its totient is φ = 7310666880.

The previous prime is 21221333317. The next prime is 21221333333. The reversal of 21221333320 is 2333312212.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a junction number, because it is equal to n+sod(n) for n = 21221333291 and 21221333300.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 23424 + ... + 207343.

It is an arithmetic number, because the mean of its divisors is an integer number (575477700).

Almost surely, 2^21221333320 is an apocalyptic number.

21221333320 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 21221333320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27622929600).

21221333320 is an abundant number, since it is smaller than the sum of its proper divisors (34024525880).

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

21221333320 is a wasteful number, since it uses less digits than its factorization.

21221333320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230819 (or 230804 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 22.

Adding to 21221333320 its reverse (2333312212), we get a palindrome (23554645532).

The spelling of 21221333320 in words is "twenty-one billion, two hundred twenty-one million, three hundred thirty-three thousand, three hundred twenty".