21013228800 has 324 divisors, whose sum is σ = 75381362784. Its totient is φ = 5584588800.

The previous prime is 21013228783. The next prime is 21013228829. The reversal of 21013228800 is 882231012.

It is a super-2 number, since 2×21013228800² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 28281229 + ... + 28281971.

Almost surely, 2^21013228800 is an apocalyptic number.

21013228800 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 21013228800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37690681392).

21013228800 is an abundant number, since it is smaller than the sum of its proper divisors (54368133984).

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

21013228800 is a wasteful number, since it uses less digits than its factorization.

21013228800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1266 (or 1244 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

Adding to 21013228800 its reverse (882231012), we get a palindrome (21895459812).

The spelling of 21013228800 in words is "twenty-one billion, thirteen million, two hundred twenty-eight thousand, eight hundred".