21356384 has 48 divisors (see below), whose sum is σ = 48803328. Its totient is φ = 9009792.

The previous prime is 21356381. The next prime is 21356429. The reversal of 21356384 is 48365312.

It is a hoax number, since the sum of its digits (32) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a self number, because there is not a number n which added to its sum of digits gives 21356384.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21356381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14297 + ... + 15719.

It is an arithmetic number, because the mean of its divisors is an integer number (1016736).

Almost surely, 2^21356384 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21356384, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24401664).

21356384 is an abundant number, since it is smaller than the sum of its proper divisors (27446944).

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

21356384 is a wasteful number, since it uses less digits than its factorization.

21356384 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1507 (or 1499 counting only the distinct ones).

The product of its digits is 17280, while the sum is 32.

The square root of 21356384 is about 4621.2967876993. The cubic root of 21356384 is about 277.4443640323. Note that the first 3 decimals are identical.

The spelling of 21356384 in words is "twenty-one million, three hundred fifty-six thousand, three hundred eighty-four".