21616304 has 10 divisors (see below), whose sum is σ = 41881620. Its totient is φ = 10808144.

The previous prime is 21616303. The next prime is 21616327. The reversal of 21616304 is 40361612.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21616304.

It is not an unprimeable number, because it can be changed into a prime (21616303) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 675494 + ... + 675525.

It is an arithmetic number, because the mean of its divisors is an integer number (4188162).

Almost surely, 2^21616304 is an apocalyptic number.

It is an amenable number.

21616304 is a deficient number, since it is larger than the sum of its proper divisors (20265316).

21616304 is a wasteful number, since it uses less digits than its factorization.

21616304 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1351027 (or 1351021 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 21616304 is about 4649.3337157059. Note that the first 3 decimals coincide. The cubic root of 21616304 is about 278.5653831943.

Adding to 21616304 its reverse (40361612), we get a palindrome (61977916).

The spelling of 21616304 in words is "twenty-one million, six hundred sixteen thousand, three hundred four".