21203144 has 16 divisors (see below), whose sum is σ = 39854220. Its totient is φ = 10575360.

The previous prime is 21203141. The next prime is 21203153. The reversal of 21203144 is 44130212.

It can be written as a sum of positive squares in 2 ways, for example, as 17322244 + 3880900 = 4162^2 + 1970^2 .

It is not an unprimeable number, because it can be changed into a prime (21203141) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 404 + ... + 6524.

Almost surely, 2^21203144 is an apocalyptic number.

It is an amenable number.

21203144 is a deficient number, since it is larger than the sum of its proper divisors (18651076).

21203144 is a wasteful number, since it uses less digits than its factorization.

21203144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6560 (or 6556 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 21203144 is about 4604.6871772141. The cubic root of 21203144 is about 276.7791816679.

Adding to 21203144 its reverse (44130212), we get a palindrome (65333356).

The spelling of 21203144 in words is "twenty-one million, two hundred three thousand, one hundred forty-four".