21104304 has 80 divisors (see below), whose sum is σ = 60662784. Its totient is φ = 6278400.

The previous prime is 21104287. The next prime is 21104311. The reversal of 21104304 is 40340112.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18799 + ... + 19889.

Almost surely, 2^21104304 is an apocalyptic number.

21104304 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 21104304, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30331392).

21104304 is an abundant number, since it is smaller than the sum of its proper divisors (39558480).

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

21104304 is a wasteful number, since it uses less digits than its factorization.

21104304 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1146 (or 1140 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 21104304 is about 4593.9420980243. The cubic root of 21104304 is about 276.3484362181.

Adding to 21104304 its reverse (40340112), we get a palindrome (61444416).

The spelling of 21104304 in words is "twenty-one million, one hundred four thousand, three hundred four".