21333384 has 48 divisors (see below), whose sum is σ = 58132620. Its totient is φ = 7067520.

The previous prime is 21333353. The next prime is 21333413. The reversal of 21333384 is 48333312.

It can be written as a sum of positive squares in 2 ways, for example, as 13616100 + 7717284 = 3690^2 + 2778^2 .

It is a super-2 number, since 2×21333384² = 910226545782912, which contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12214 + ... + 13850.

Almost surely, 2^21333384 is an apocalyptic number.

21333384 is a gapful number since it is divisible by the number (24) 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 21333384, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29066310).

21333384 is an abundant number, since it is smaller than the sum of its proper divisors (36799236).

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

21333384 is a wasteful number, since it uses less digits than its factorization.

21333384 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1830 (or 1823 counting only the distinct ones).

The product of its digits is 5184, while the sum is 27.

The square root of 21333384 is about 4618.8076383413. The cubic root of 21333384 is about 277.3447293045.

Adding to 21333384 its reverse (48333312), we get a palindrome (69666696).

The spelling of 21333384 in words is "twenty-one million, three hundred thirty-three thousand, three hundred eighty-four".