21432304 has 20 divisors (see below), whose sum is σ = 43711240. Its totient is φ = 10152000.

The previous prime is 21432293. The next prime is 21432311. The reversal of 21432304 is 40323412.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34947 + ... + 35554.

It is an arithmetic number, because the mean of its divisors is an integer number (2185562).

Almost surely, 2^21432304 is an apocalyptic number.

It is an amenable number.

21432304 is an abundant number, since it is smaller than the sum of its proper divisors (22278936).

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

21432304 is a wasteful number, since it uses less digits than its factorization.

21432304 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70528 (or 70522 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 19.

The square root of 21432304 is about 4629.5036451006. The cubic root of 21432304 is about 277.7727383738.

Adding to 21432304 its reverse (40323412), we get a palindrome (61755716).

It can be divided in two parts, 21432 and 304, that added together give a triangular number (21736 = T₂₀₈).

The spelling of 21432304 in words is "twenty-one million, four hundred thirty-two thousand, three hundred four".