21034543 has 2 divisors, whose sum is σ = 21034544. Its totient is φ = 21034542.

The previous prime is 21034513. The next prime is 21034561. The reversal of 21034543 is 34543012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21034543 - 2¹³ = 21026351 is a prime.

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

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21034513) 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 as a sum of consecutive naturals, namely, 10517271 + 10517272.

It is an arithmetic number, because the mean of its divisors is an integer number (10517272).

Almost surely, 2^21034543 is an apocalyptic number.

21034543 is a deficient number, since it is larger than the sum of its proper divisors (1).

21034543 is an equidigital number, since it uses as much as digits as its factorization.

21034543 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1440, while the sum is 22.

The square root of 21034543 is about 4586.3430966294. The cubic root of 21034543 is about 276.0436070215.

Adding to 21034543 its reverse (34543012), we get a palindrome (55577555).

The spelling of 21034543 in words is "twenty-one million, thirty-four thousand, five hundred forty-three".