21115500064943 has 2 divisors, whose sum is σ = 21115500064944. Its totient is φ = 21115500064942.

The previous prime is 21115500064933. The next prime is 21115500065041. The reversal of 21115500064943 is 34946000551112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21115500064943 - 2⁴ = 21115500064927 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21115500064943.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21115500064933) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10557750032471 + 10557750032472.

It is an arithmetic number, because the mean of its divisors is an integer number (10557750032472).

Almost surely, 2^{21115500064943} is an apocalyptic number.

21115500064943 is a deficient number, since it is larger than the sum of its proper divisors (1).

21115500064943 is an equidigital number, since it uses as much as digits as its factorization.

21115500064943 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 129600, while the sum is 41.

The spelling of 21115500064943 in words is "twenty-one trillion, one hundred fifteen billion, five hundred million, sixty-four thousand, nine hundred forty-three".