21504352 has 48 divisors (see below), whose sum is σ = 45102960. Its totient is φ = 10063872.

The previous prime is 21504349. The next prime is 21504361. The reversal of 21504352 is 25340512.

It is a congruent number.

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 7 ways as a sum of consecutive naturals, for example, 68548 + ... + 68860.

It is an arithmetic number, because the mean of its divisors is an integer number (939645).

Almost surely, 2^21504352 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 21504352, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22551480).

21504352 is an abundant number, since it is smaller than the sum of its proper divisors (23598608).

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

21504352 is a wasteful number, since it uses less digits than its factorization.

21504352 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 455 (or 447 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 22.

The square root of 21504352 is about 4637.2785122311. The cubic root of 21504352 is about 278.0836488959.

Adding to 21504352 its reverse (25340512), we get a palindrome (46844864).

The spelling of 21504352 in words is "twenty-one million, five hundred four thousand, three hundred fifty-two".