21165563036489 has 2 divisors, whose sum is σ = 21165563036490. Its totient is φ = 21165563036488.

The previous prime is 21165563036479. The next prime is 21165563036531. The reversal of 21165563036489 is 98463036556112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17568395612089 + 3597167424400 = 4191467^2 + 1896620^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21165563036489 is a prime.

It is not a weakly prime, because it can be changed into another prime (21165563036479) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10582781518244 + 10582781518245.

It is an arithmetic number, because the mean of its divisors is an integer number (10582781518245).

Almost surely, 2^{21165563036489} is an apocalyptic number.

It is an amenable number.

21165563036489 is a deficient number, since it is larger than the sum of its proper divisors (1).

21165563036489 is an equidigital number, since it uses as much as digits as its factorization.

21165563036489 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 27993600, while the sum is 59.

The spelling of 21165563036489 in words is "twenty-one trillion, one hundred sixty-five billion, five hundred sixty-three million, thirty-six thousand, four hundred eighty-nine".