21320400000 has 384 divisors, whose sum is σ = 71873524800. Its totient is φ = 5598720000.

The previous prime is 21320399993. The next prime is 21320400007. The reversal of 21320400000 is 402312.

It is an interprime number because it is at equal distance from previous prime (21320399993) and next prime (21320400007).

It is a tau number, because it is divible by the number of its divisors (384).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is not an unprimeable number, because it can be changed into a prime (21320400007) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 130799919 + ... + 130800081.

Almost surely, 2^21320400000 is an apocalyptic number.

21320400000 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 21320400000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35936762400).

21320400000 is an abundant number, since it is smaller than the sum of its proper divisors (50553124800).

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

21320400000 is an equidigital number, since it uses as much as digits as its factorization.

21320400000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 314 (or 282 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 12.

Adding to 21320400000 its reverse (402312), we get a palindrome (21320802312).

The spelling of 21320400000 in words is "twenty-one billion, three hundred twenty million, four hundred thousand".