21540304 has 20 divisors (see below), whose sum is σ = 41826564. Its totient is φ = 10746368.

The previous prime is 21540289. The next prime is 21540307. The reversal of 21540304 is 40304512.

It can be written as a sum of positive squares in 2 ways, for example, as 12250000 + 9290304 = 3500^2 + 3048^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21540307) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 7704 + ... + 10120.

Almost surely, 2^21540304 is an apocalyptic number.

It is an amenable number.

21540304 is a deficient number, since it is larger than the sum of its proper divisors (20286260).

21540304 is a wasteful number, since it uses less digits than its factorization.

21540304 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2982 (or 2976 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 19.

The square root of 21540304 is about 4641.1533049448. The cubic root of 21540304 is about 278.2385337767.

Adding to 21540304 its reverse (40304512), we get a palindrome (61844816).

The spelling of 21540304 in words is "twenty-one million, five hundred forty thousand, three hundred four".