21304430 has 16 divisors (see below), whose sum is σ = 43826400. Its totient is φ = 7304352.

The previous prime is 21304427. The next prime is 21304441. The reversal of 21304430 is 3440312.

It is a junction number, because it is equal to n+sod(n) for n = 21304399 and 21304408.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 152105 + ... + 152244.

It is an arithmetic number, because the mean of its divisors is an integer number (2739150).

Almost surely, 2^21304430 is an apocalyptic number.

21304430 is an abundant number, since it is smaller than the sum of its proper divisors (22521970).

21304430 is a wasteful number, since it uses less digits than its factorization.

21304430 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 304363.

The product of its (nonzero) digits is 288, while the sum is 17.

The square root of 21304430 is about 4615.6722153983. The cubic root of 21304430 is about 277.2192003064.

Adding to 21304430 its reverse (3440312), we get a palindrome (24744742).

The spelling of 21304430 in words is "twenty-one million, three hundred four thousand, four hundred thirty".