21000331320 has 256 divisors, whose sum is σ = 65858365440. Its totient is φ = 5353463808.

The previous prime is 21000331307. The next prime is 21000331349. The reversal of 21000331320 is 2313300012.

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 21000331320.

It is a congruent number.

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 63 ways as a sum of consecutive naturals, for example, 52897362 + ... + 52897758.

It is an arithmetic number, because the mean of its divisors is an integer number (257259240).

Almost surely, 2^21000331320 is an apocalyptic number.

21000331320 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 21000331320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32929182720).

21000331320 is an abundant number, since it is smaller than the sum of its proper divisors (44858034120).

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

21000331320 is a wasteful number, since it uses less digits than its factorization.

21000331320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 654 (or 650 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 15.

Adding to 21000331320 its reverse (2313300012), we get a palindrome (23313631332).

The spelling of 21000331320 in words is "twenty-one billion, three hundred thirty-one thousand, three hundred twenty".