21012200320 has 256 divisors, whose sum is σ = 54286848000. Its totient is φ = 7753605120.

The previous prime is 21012200267. The next prime is 21012200323. The reversal of 21012200320 is 2300221012.

It is a self number, because there is not a number n which added to its sum of digits gives 21012200320.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012200323) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 110011425 + ... + 110011615.

It is an arithmetic number, because the mean of its divisors is an integer number (212058000).

Almost surely, 2^21012200320 is an apocalyptic number.

21012200320 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 21012200320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27143424000).

21012200320 is an abundant number, since it is smaller than the sum of its proper divisors (33274647680).

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

21012200320 is a wasteful number, since it uses less digits than its factorization.

21012200320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 421 (or 409 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 13.

Adding to 21012200320 its reverse (2300221012), we get a palindrome (23312421332).

The spelling of 21012200320 in words is "twenty-one billion, twelve million, two hundred thousand, three hundred twenty".