21412543 has 4 divisors (see below), whose sum is σ = 21446488. Its totient is φ = 21378600.

The previous prime is 21412513. The next prime is 21412549. The reversal of 21412543 is 34521412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21412543 - 2²¹ = 19315391 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 (21412549) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16008 + ... + 17293.

It is an arithmetic number, because the mean of its divisors is an integer number (5361622).

Almost surely, 2^21412543 is an apocalyptic number.

21412543 is a deficient number, since it is larger than the sum of its proper divisors (33945).

21412543 is an equidigital number, since it uses as much as digits as its factorization.

21412543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33944.

The product of its digits is 960, while the sum is 22.

The square root of 21412543 is about 4627.3689068411. The cubic root of 21412543 is about 277.6873415050.

Adding to 21412543 its reverse (34521412), we get a palindrome (55933955).

The spelling of 21412543 in words is "twenty-one million, four hundred twelve thousand, five hundred forty-three".