21440384 has 32 divisors (see below), whose sum is σ = 48817200. Its totient is φ = 9188352.

The previous prime is 21440369. The next prime is 21440387. The reversal of 21440384 is 48304412.

It is a tau number, because it is divible by the number of its divisors (32).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21440387) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11069 + ... + 12860.

Almost surely, 2^21440384 is an apocalyptic number.

It is an amenable number.

21440384 is an abundant number, since it is smaller than the sum of its proper divisors (27376816).

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

21440384 is an equidigital number, since it uses as much as digits as its factorization.

21440384 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23950 (or 23938 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 26.

The square root of 21440384 is about 4630.3762266149. The cubic root of 21440384 is about 277.8076408546.

Adding to 21440384 its reverse (48304412), we get a palindrome (69744796).

The spelling of 21440384 in words is "twenty-one million, four hundred forty thousand, three hundred eighty-four".