21104544 has 24 divisors (see below), whose sum is σ = 55399680. Its totient is φ = 7034816.

The previous prime is 21104543. The next prime is 21104549. The reversal of 21104544 is 44540112.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21104544.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21104543) 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, 109824 + ... + 110015.

It is an arithmetic number, because the mean of its divisors is an integer number (2308320).

Almost surely, 2^21104544 is an apocalyptic number.

21104544 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21104544 is an abundant number, since it is smaller than the sum of its proper divisors (34295136).

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

21104544 is a wasteful number, since it uses less digits than its factorization.

21104544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 219852 (or 219844 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 21.

The square root of 21104544 is about 4593.9682193067. The cubic root of 21104544 is about 276.3494837670.

Adding to 21104544 its reverse (44540112), we get a palindrome (65644656).

The spelling of 21104544 in words is "twenty-one million, one hundred four thousand, five hundred forty-four".