21136637258717 has 2 divisors, whose sum is σ = 21136637258718. Its totient is φ = 21136637258716.

The previous prime is 21136637258699. The next prime is 21136637258771. The reversal of 21136637258717 is 71785273663112.

Together with next prime (21136637258771) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20303909832196 + 832727426521 = 4505986^2 + 912539^2 .

It is a cyclic number.

It is not a de Polignac number, because 21136637258717 - 2²² = 21136633064413 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21136637258797) 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, 10568318629358 + 10568318629359.

It is an arithmetic number, because the mean of its divisors is an integer number (10568318629359).

Almost surely, 2^{21136637258717} is an apocalyptic number.

It is an amenable number.

21136637258717 is a deficient number, since it is larger than the sum of its proper divisors (1).

21136637258717 is an equidigital number, since it uses as much as digits as its factorization.

21136637258717 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17781120, while the sum is 59.

The spelling of 21136637258717 in words is "twenty-one trillion, one hundred thirty-six billion, six hundred thirty-seven million, two hundred fifty-eight thousand, seven hundred seventeen".