21164543 has 8 divisors (see below), whose sum is σ = 21778848. Its totient is φ = 20558304.

The previous prime is 21164509. The next prime is 21164567. The reversal of 21164543 is 34546112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21164543 - 2¹⁶ = 21099007 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 (21164593) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3521 + ... + 7397.

It is an arithmetic number, because the mean of its divisors is an integer number (2722356).

Almost surely, 2^21164543 is an apocalyptic number.

21164543 is a deficient number, since it is larger than the sum of its proper divisors (614305).

21164543 is a wasteful number, since it uses less digits than its factorization.

21164543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4033.

The product of its digits is 2880, while the sum is 26.

The square root of 21164543 is about 4600.4937778460. The cubic root of 21164543 is about 276.6111178618.

The spelling of 21164543 in words is "twenty-one million, one hundred sixty-four thousand, five hundred forty-three".