21043534091 has 2 divisors, whose sum is σ = 21043534092. Its totient is φ = 21043534090.

The previous prime is 21043534069. The next prime is 21043534121. The reversal of 21043534091 is 19043534012.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21043534091 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (21043534021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10521767045 + 10521767046.

It is an arithmetic number, because the mean of its divisors is an integer number (10521767046).

Almost surely, 2^21043534091 is an apocalyptic number.

21043534091 is a deficient number, since it is larger than the sum of its proper divisors (1).

21043534091 is an equidigital number, since it uses as much as digits as its factorization.

21043534091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12960, while the sum is 32.

The spelling of 21043534091 in words is "twenty-one billion, forty-three million, five hundred thirty-four thousand, ninety-one".