21153204 has 24 divisors (see below), whose sum is σ = 54841920. Its totient is φ = 7051032.

The previous prime is 21153199. The next prime is 21153227. The reversal of 21153204 is 40235112.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 97824 + ... + 98039.

It is an arithmetic number, because the mean of its divisors is an integer number (2285080).

Almost surely, 2^21153204 is an apocalyptic number.

It is an amenable number.

21153204 is an abundant number, since it is smaller than the sum of its proper divisors (33688716).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21153204 is a wasteful number, since it uses less digits than its factorization.

21153204 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195876 (or 195868 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 21153204 is about 4599.2612450262. The cubic root of 21153204 is about 276.5617104832.

Adding to 21153204 its reverse (40235112), we get a palindrome (61388316).

The spelling of 21153204 in words is "twenty-one million, one hundred fifty-three thousand, two hundred four".