21543522043 has 4 divisors (see below), whose sum is σ = 21567171168. Its totient is φ = 21519872920.

The previous prime is 21543522029. The next prime is 21543522067. The reversal of 21543522043 is 34022534512.

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 21543522043 - 2¹³ = 21543513851 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21543521996 and 21543522014.

It is not an unprimeable number, because it can be changed into a prime (21543522643) 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, 11823196 + ... + 11825017.

It is an arithmetic number, because the mean of its divisors is an integer number (5391792792).

Almost surely, 2^21543522043 is an apocalyptic number.

21543522043 is a deficient number, since it is larger than the sum of its proper divisors (23649125).

21543522043 is an equidigital number, since it uses as much as digits as its factorization.

21543522043 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23649124.

The product of its (nonzero) digits is 28800, while the sum is 31.

The spelling of 21543522043 in words is "twenty-one billion, five hundred forty-three million, five hundred twenty-two thousand, forty-three".