21320320320 has 336 divisors, whose sum is σ = 79197994512. Its totient is φ = 5233213440.

The previous prime is 21320320319. The next prime is 21320320403. The reversal of 21320320320 is 2302302312.

It is a happy number.

21320320320 is a `hidden beast` number, since 2 + 1 + 3 + 20 + 320 + 320 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 41679936 + 21278640384 = 6456^2 + 145872^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21320320293 and 21320320302.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 19505694 + ... + 19506786.

It is an arithmetic number, because the mean of its divisors is an integer number (235708317).

Almost surely, 2^21320320320 is an apocalyptic number.

21320320320 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 21320320320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39598997256).

21320320320 is an abundant number, since it is smaller than the sum of its proper divisors (57877674192).

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

21320320320 is a wasteful number, since it uses less digits than its factorization.

21320320320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1650 (or 1637 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 18.

Adding to 21320320320 its reverse (2302302312), we get a palindrome (23622622632).

The spelling of 21320320320 in words is "twenty-one billion, three hundred twenty million, three hundred twenty thousand, three hundred twenty".