21353204 has 6 divisors (see below), whose sum is σ = 37368114. Its totient is φ = 10676600.

The previous prime is 21353201. The next prime is 21353219. The reversal of 21353204 is 40235312.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 21141604 + 211600 = 4598^2 + 460^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21353201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2669147 + ... + 2669154.

It is an arithmetic number, because the mean of its divisors is an integer number (6228019).

Almost surely, 2^21353204 is an apocalyptic number.

It is an amenable number.

21353204 is a deficient number, since it is larger than the sum of its proper divisors (16014910).

21353204 is a wasteful number, since it uses less digits than its factorization.

21353204 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5338305 (or 5338303 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 20.

The square root of 21353204 is about 4620.9527156204. The cubic root of 21353204 is about 277.4305927111.

Adding to 21353204 its reverse (40235312), we get a palindrome (61588516).

The spelling of 21353204 in words is "twenty-one million, three hundred fifty-three thousand, two hundred four".