21267543 has 16 divisors (see below), whose sum is σ = 31239936. Its totient is φ = 12762240.

The previous prime is 21267523. The next prime is 21267577. The reversal of 21267543 is 34576212.

It is not a de Polignac number, because 21267543 - 2⁹ = 21267031 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21267543.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21267503) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 271 + ... + 6527.

It is an arithmetic number, because the mean of its divisors is an integer number (1952496).

Almost surely, 2^21267543 is an apocalyptic number.

21267543 is a deficient number, since it is larger than the sum of its proper divisors (9972393).

21267543 is a wasteful number, since it uses less digits than its factorization.

21267543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6374.

The product of its digits is 10080, while the sum is 30.

The square root of 21267543 is about 4611.6746416025. The cubic root of 21267543 is about 277.0591132252.

It can be divided in two parts, 2126 and 7543, that added together give a palindrome (9669).

The spelling of 21267543 in words is "twenty-one million, two hundred sixty-seven thousand, five hundred forty-three".