21144204 has 36 divisors (see below), whose sum is σ = 53783184. Its totient is φ = 7003872.

The previous prime is 21144203. The next prime is 21144223. The reversal of 21144204 is 40244112.

It is a tau number, because it is divible by the number of its divisors (36).

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

It is not an unprimeable number, because it can be changed into a prime (21144203) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4254 + ... + 7770.

Almost surely, 2^21144204 is an apocalyptic number.

It is an amenable number.

21144204 is an abundant number, since it is smaller than the sum of its proper divisors (32638980).

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

21144204 is a wasteful number, since it uses less digits than its factorization.

21144204 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3694 (or 3689 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 21144204 is about 4598.2827229304. The cubic root of 21144204 is about 276.5224822497.

Adding to 21144204 its reverse (40244112), we get a palindrome (61388316).

The spelling of 21144204 in words is "twenty-one million, one hundred forty-four thousand, two hundred four".