21343543 has 4 divisors (see below), whose sum is σ = 22985368. Its totient is φ = 19701720.

The previous prime is 21343519. The next prime is 21343579. The reversal of 21343543 is 34534312.

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 21343543 - 2¹³ = 21335351 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 (21343513) 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, 820893 + ... + 820918.

It is an arithmetic number, because the mean of its divisors is an integer number (5746342).

Almost surely, 2^21343543 is an apocalyptic number.

21343543 is a deficient number, since it is larger than the sum of its proper divisors (1641825).

21343543 is a wasteful number, since it uses less digits than its factorization.

21343543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1641824.

The product of its digits is 4320, while the sum is 25.

The square root of 21343543 is about 4619.9072501512. The cubic root of 21343543 is about 277.3887463559.

Adding to 21343543 its reverse (34534312), we get a palindrome (55877855).

The spelling of 21343543 in words is "twenty-one million, three hundred forty-three thousand, five hundred forty-three".