21144243 has 16 divisors (see below), whose sum is σ = 30360960. Its totient is φ = 13040256.

The previous prime is 21144229. The next prime is 21144259. The reversal of 21144243 is 34244112.

It is not a de Polignac number, because 21144243 - 2¹⁴ = 21127859 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21144203) 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 15 ways as a sum of consecutive naturals, for example, 505 + ... + 6522.

It is an arithmetic number, because the mean of its divisors is an integer number (1897560).

Almost surely, 2^21144243 is an apocalyptic number.

21144243 is a deficient number, since it is larger than the sum of its proper divisors (9216717).

21144243 is a wasteful number, since it uses less digits than its factorization.

21144243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7106.

The product of its digits is 768, while the sum is 21.

The square root of 21144243 is about 4598.2869636420. The cubic root of 21144243 is about 276.5226522627.

Adding to 21144243 its reverse (34244112), we get a palindrome (55388355).

The spelling of 21144243 in words is "twenty-one million, one hundred forty-four thousand, two hundred forty-three".