21452543 has 12 divisors (see below), whose sum is σ = 25075440. Its totient is φ = 18299232.

The previous prime is 21452533. The next prime is 21452549. The reversal of 21452543 is 34525412.

It is a happy number.

It is not a de Polignac number, because 21452543 - 2⁶ = 21452479 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21452549) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10478 + ... + 12356.

It is an arithmetic number, because the mean of its divisors is an integer number (2089620).

Almost surely, 2^21452543 is an apocalyptic number.

21452543 is a deficient number, since it is larger than the sum of its proper divisors (3622897).

21452543 is a wasteful number, since it uses less digits than its factorization.

21452543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2126 (or 2119 counting only the distinct ones).

The product of its digits is 4800, while the sum is 26.

The square root of 21452543 is about 4631.6890007858. The cubic root of 21452543 is about 277.8601465182.

Adding to 21452543 its reverse (34525412), we get a palindrome (55977955).

The spelling of 21452543 in words is "twenty-one million, four hundred fifty-two thousand, five hundred forty-three".