21344440320 has 624 divisors, whose sum is σ = 86113228032. Its totient is φ = 4789370880.

The previous prime is 21344440301. The next prime is 21344440373. The reversal of 21344440320 is 2304444312.

It is a happy number.

21344440320 is a `hidden beast` number, since 213 + 4 + 4 + 440 + 3 + 2 + 0 = 666.

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, 91606924 + ... + 91607156.

It is an arithmetic number, because the mean of its divisors is an integer number (138001968).

Almost surely, 2^21344440320 is an apocalyptic number.

21344440320 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 21344440320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43056614016).

21344440320 is an abundant number, since it is smaller than the sum of its proper divisors (64768787712).

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

21344440320 is a wasteful number, since it uses less digits than its factorization.

21344440320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 346 (or 321 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 27.

Adding to 21344440320 its reverse (2304444312), we get a palindrome (23648884632).

The spelling of 21344440320 in words is "twenty-one billion, three hundred forty-four million, four hundred forty thousand, three hundred twenty".