21334320 has 320 divisors, whose sum is σ = 89994240. Its totient is φ = 4534272.

The previous prime is 21334319. The next prime is 21334333. The reversal of 21334320 is 2343312.

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 = 21334293 and 21334302.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 256999 + ... + 257081.

It is an arithmetic number, because the mean of its divisors is an integer number (281232).

Almost surely, 2^21334320 is an apocalyptic number.

21334320 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 21334320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44997120).

21334320 is an abundant number, since it is smaller than the sum of its proper divisors (68659920).

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

21334320 is a wasteful number, since it uses less digits than its factorization.

21334320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129 (or 117 counting only the distinct ones).

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

The square root of 21334320 is about 4618.9089620818. The cubic root of 21334320 is about 277.3487854022.

Adding to 21334320 its reverse (2343312), we get a palindrome (23677632).

The spelling of 21334320 in words is "twenty-one million, three hundred thirty-four thousand, three hundred twenty".