21304004 has 12 divisors (see below), whose sum is σ = 37363200. Its totient is φ = 10628808.

The previous prime is 21304001. The next prime is 21304027. The reversal of 21304004 is 40040312.

It is a self number, because there is not a number n which added to its sum of digits gives 21304004.

It is not an unprimeable number, because it can be changed into a prime (21304001) 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, 3644 + ... + 7475.

It is an arithmetic number, because the mean of its divisors is an integer number (3113600).

Almost surely, 2^21304004 is an apocalyptic number.

It is an amenable number.

21304004 is a deficient number, since it is larger than the sum of its proper divisors (16059196).

21304004 is a wasteful number, since it uses less digits than its factorization.

21304004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11602 (or 11600 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 14.

The square root of 21304004 is about 4615.6260680432. The cubic root of 21304004 is about 277.2173525504.

Adding to 21304004 its reverse (40040312), we get a palindrome (61344316).

The spelling of 21304004 in words is "twenty-one million, three hundred four thousand, four".