21086358986765 has 12 divisors (see below), whose sum is σ = 26879635471476. Its totient is φ = 15876787941888.

The previous prime is 21086358986753. The next prime is 21086358986789. The reversal of 21086358986765 is 56768985368012.

It can be written as a sum of positive squares in 6 ways, for example, as 6901659664201 + 14184699322564 = 2627101^2 + 3766258^2 .

It is not a de Polignac number, because 21086358986765 - 2¹² = 21086358982669 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21086358986692 and 21086358986701.

It is a congruent number.

It is an unprimeable number.

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 in 11 ways as a sum of consecutive naturals, for example, 7296316544 + ... + 7296319433.

It is an arithmetic number, because the mean of its divisors is an integer number (2239969622623).

Almost surely, 2^{21086358986765} is an apocalyptic number.

It is an amenable number.

21086358986765 is a deficient number, since it is larger than the sum of its proper divisors (5793276484711).

21086358986765 is a wasteful number, since it uses less digits than its factorization.

21086358986765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14592636016 (or 14592635999 counting only the distinct ones).

The product of its (nonzero) digits is 1045094400, while the sum is 74.

The spelling of 21086358986765 in words is "twenty-one trillion, eighty-six billion, three hundred fifty-eight million, nine hundred eighty-six thousand, seven hundred sixty-five".