21043534111 has 4 divisors (see below), whose sum is σ = 21722357824. Its totient is φ = 20364710400.

The previous prime is 21043534091. The next prime is 21043534121. The reversal of 21043534111 is 11143534012.

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 21043534111 - 2¹⁷ = 21043403039 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 (21043534121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 339411810 + ... + 339411871.

It is an arithmetic number, because the mean of its divisors is an integer number (5430589456).

Almost surely, 2^21043534111 is an apocalyptic number.

21043534111 is a deficient number, since it is larger than the sum of its proper divisors (678823713).

21043534111 is an equidigital number, since it uses as much as digits as its factorization.

21043534111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 678823712.

The product of its (nonzero) digits is 1440, while the sum is 25.

Subtracting from 21043534111 its reverse (11143534012), we obtain a palindrome (9900000099).

The spelling of 21043534111 in words is "twenty-one billion, forty-three million, five hundred thirty-four thousand, one hundred eleven".