21310304 has 12 divisors (see below), whose sum is σ = 41954724. Its totient is φ = 10655136.

The previous prime is 21310301. The next prime is 21310309. The reversal of 21310304 is 40301312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21310301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332942 + ... + 333005.

It is an arithmetic number, because the mean of its divisors is an integer number (3496227).

Almost surely, 2^21310304 is an apocalyptic number.

It is an amenable number.

21310304 is a deficient number, since it is larger than the sum of its proper divisors (20644420).

21310304 is an equidigital number, since it uses as much as digits as its factorization.

21310304 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 665957 (or 665949 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 21310304 is about 4616.3084818933. The cubic root of 21310304 is about 277.2446760087.

Adding to 21310304 its reverse (40301312), we get a palindrome (61611616).

The spelling of 21310304 in words is "twenty-one million, three hundred ten thousand, three hundred four".