21044543 has 8 divisors (see below), whose sum is σ = 22741488. Its totient is φ = 19358784.

The previous prime is 21044531. The next prime is 21044557. The reversal of 21044543 is 34544012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21044543 - 2⁶ = 21044479 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21044743) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1355 + ... + 6627.

It is an arithmetic number, because the mean of its divisors is an integer number (2842686).

Almost surely, 2^21044543 is an apocalyptic number.

21044543 is a deficient number, since it is larger than the sum of its proper divisors (1696945).

21044543 is a wasteful number, since it uses less digits than its factorization.

21044543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5593.

The product of its (nonzero) digits is 1920, while the sum is 23.

The square root of 21044543 is about 4587.4331602760. The cubic root of 21044543 is about 276.0873445812.

Adding to 21044543 its reverse (34544012), we get a palindrome (55588555).

The spelling of 21044543 in words is "twenty-one million, forty-four thousand, five hundred forty-three".