21522320400000 has 768 divisors, whose sum is σ = 84299644477440. Its totient is φ = 4760640000000.

The previous prime is 21522320399963. The next prime is 21522320400001. The reversal of 21522320400000 is 402322512.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a self number, because there is not a number n which added to its sum of digits gives 21522320400000.

It is not an unprimeable number, because it can be changed into a prime (21522320400001) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 260358675 + ... + 260441325.

It is an arithmetic number, because the mean of its divisors is an integer number (109765162080).

Almost surely, 2^{21522320400000} is an apocalyptic number.

21522320400000 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 21522320400000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42149822238720).

21522320400000 is an abundant number, since it is smaller than the sum of its proper divisors (62777324077440).

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

21522320400000 is an frugal number, since it uses more digits than its factorization.

21522320400000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82731 (or 82699 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 21.

Adding to 21522320400000 its reverse (402322512), we get a palindrome (21522722722512).

The spelling of 21522320400000 in words is "twenty-one trillion, five hundred twenty-two billion, three hundred twenty million, four hundred thousand".