21531021320000 has 140 divisors (see below), whose sum is σ = 53523117148116. Its totient is φ = 8590924800000.

The previous prime is 21531021319987. The next prime is 21531021320047. The reversal of 21531021320000 is 2312013512.

It can be written as a sum of positive squares in 10 ways, for example, as 2753289764416 + 18777731555584 = 1659304^2 + 4333328^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 15368834 + ... + 16711166.

Almost surely, 2^{21531021320000} is an apocalyptic number.

21531021320000 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 21531021320000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26761558574058).

21531021320000 is an abundant number, since it is smaller than the sum of its proper divisors (31992095828116).

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

21531021320000 is an equidigital number, since it uses as much as digits as its factorization.

21531021320000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1342766 (or 1342741 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 20.

Adding to 21531021320000 its reverse (2312013512), we get a palindrome (21533333333512).

The spelling of 21531021320000 in words is "twenty-one trillion, five hundred thirty-one billion, twenty-one million, three hundred twenty thousand".