21033320 has 64 divisors (see below), whose sum is σ = 59011200. Its totient is φ = 6554880.

The previous prime is 21033319. The next prime is 21033329. The reversal of 21033320 is 2333012.

It is a Harshad number since it is a multiple of its sum of digits (14).

It is a junction number, because it is equal to n+sod(n) for n = 21033295 and 21033304.

It is not an unprimeable number, because it can be changed into a prime (21033329) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 335 + ... + 6494.

It is an arithmetic number, because the mean of its divisors is an integer number (922050).

Almost surely, 2^21033320 is an apocalyptic number.

21033320 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 21033320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29505600).

21033320 is an abundant number, since it is smaller than the sum of its proper divisors (37977880).

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

21033320 is a wasteful number, since it uses less digits than its factorization.

21033320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6858 (or 6854 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 14.

The square root of 21033320 is about 4586.2097640644. The cubic root of 21033320 is about 276.0382569667.

Adding to 21033320 its reverse (2333012), we get a palindrome (23366332).

The spelling of 21033320 in words is "twenty-one million, thirty-three thousand, three hundred twenty".