21144252 has 24 divisors (see below), whose sum is σ = 49818496. Its totient is φ = 6979248.

The previous prime is 21144229. The next prime is 21144259. The reversal of 21144252 is 25244112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21144259) by changing a digit.

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, 7318 + ... + 9789.

Almost surely, 2^21144252 is an apocalyptic number.

It is an amenable number.

21144252 is an abundant number, since it is smaller than the sum of its proper divisors (28674244).

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

21144252 is a wasteful number, since it uses less digits than its factorization.

21144252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17217 (or 17215 counting only the distinct ones).

The product of its digits is 640, while the sum is 21.

The square root of 21144252 is about 4598.2879422672. The cubic root of 21144252 is about 276.5226914964.

Adding to 21144252 its reverse (25244112), we get a palindrome (46388364).

The spelling of 21144252 in words is "twenty-one million, one hundred forty-four thousand, two hundred fifty-two".