16787023256821 has 2 divisors, whose sum is σ = 16787023256822. Its totient is φ = 16787023256820.

The previous prime is 16787023256779. The next prime is 16787023256837. The reversal of 16787023256821 is 12865232078761.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16320105234225 + 466918022596 = 4039815^2 + 683314^2 .

It is a cyclic number.

It is not a de Polignac number, because 16787023256821 - 2¹⁵ = 16787023224053 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16787023256321) 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, 8393511628410 + 8393511628411.

It is an arithmetic number, because the mean of its divisors is an integer number (8393511628411).

Almost surely, 2^{16787023256821} is an apocalyptic number.

It is an amenable number.

16787023256821 is a deficient number, since it is larger than the sum of its proper divisors (1).

16787023256821 is an equidigital number, since it uses as much as digits as its factorization.

16787023256821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13547520, while the sum is 58.

The spelling of 16787023256821 in words is "sixteen trillion, seven hundred eighty-seven billion, twenty-three million, two hundred fifty-six thousand, eight hundred twenty-one".