16868567021809 has 2 divisors, whose sum is σ = 16868567021810. Its totient is φ = 16868567021808.

The previous prime is 16868567021633. The next prime is 16868567021851. The reversal of 16868567021809 is 90812076586861.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11323036560784 + 5545530461025 = 3364972^2 + 2354895^2 .

It is a cyclic number.

It is not a de Polignac number, because 16868567021809 - 2⁹ = 16868567021297 is a prime.

It is not a weakly prime, because it can be changed into another prime (16868567021609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8434283510904 + 8434283510905.

It is an arithmetic number, because the mean of its divisors is an integer number (8434283510905).

Almost surely, 2^{16868567021809} is an apocalyptic number.

It is an amenable number.

16868567021809 is a deficient number, since it is larger than the sum of its proper divisors (1).

16868567021809 is an equidigital number, since it uses as much as digits as its factorization.

16868567021809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 69672960, while the sum is 67.

The spelling of 16868567021809 in words is "sixteen trillion, eight hundred sixty-eight billion, five hundred sixty-seven million, twenty-one thousand, eight hundred nine".