21634304 has 18 divisors (see below), whose sum is σ = 43184610. Its totient is φ = 10817024.

The previous prime is 21634279. The next prime is 21634309. The reversal of 21634304 is 40343612.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 19784704 + 1849600 = 4448^2 + 1360^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21634304.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21634309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41999 + ... + 42510.

It is an arithmetic number, because the mean of its divisors is an integer number (2399145).

Almost surely, 2^21634304 is an apocalyptic number.

It is an amenable number.

21634304 is a deficient number, since it is larger than the sum of its proper divisors (21550306).

21634304 is an frugal number, since it uses more digits than its factorization.

21634304 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84525 (or 84511 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 23.

The square root of 21634304 is about 4651.2690741345. The cubic root of 21634304 is about 278.6426826525.

Adding to 21634304 its reverse (40343612), we get a palindrome (61977916).

The spelling of 21634304 in words is "twenty-one million, six hundred thirty-four thousand, three hundred four".