21000384 has 70 divisors (see below), whose sum is σ = 62267084. Its totient is φ = 6998400.

The previous prime is 21000367. The next prime is 21000391. The reversal of 21000384 is 48300012.

It is a happy number.

It is a super-2 number, since 2×21000384² = 882032256294912, which contains 22 as substring.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 3159 + ... + 7209.

Almost surely, 2^21000384 is an apocalyptic number.

21000384 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 21000384, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31133542).

21000384 is an abundant number, since it is smaller than the sum of its proper divisors (41266700).

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

21000384 is an equidigital number, since it uses as much as digits as its factorization.

21000384 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4075 (or 4056 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 21000384 is about 4582.6175925992. The cubic root of 21000384 is about 275.8940992578.

Adding to 21000384 its reverse (48300012), we get a palindrome (69300396).

The spelling of 21000384 in words is "twenty-one million, three hundred eighty-four", and thus it is an aban number.