21304144 has 20 divisors (see below), whose sum is σ = 41490400. Its totient is φ = 10596960.

The previous prime is 21304139. The next prime is 21304147. The reversal of 21304144 is 44140312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21304147) 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, 162 + ... + 6529.

It is an arithmetic number, because the mean of its divisors is an integer number (2074520).

Almost surely, 2^21304144 is an apocalyptic number.

It is an amenable number.

21304144 is a deficient number, since it is larger than the sum of its proper divisors (20186256).

21304144 is a wasteful number, since it uses less digits than its factorization.

21304144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6898 (or 6892 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 19.

The square root of 21304144 is about 4615.6412338916. The cubic root of 21304144 is about 277.2179597969.

Adding to 21304144 its reverse (44140312), we get a palindrome (65444456).

The spelling of 21304144 in words is "twenty-one million, three hundred four thousand, one hundred forty-four".