16717506565681 has 2 divisors, whose sum is σ = 16717506565682. Its totient is φ = 16717506565680.

The previous prime is 16717506565649. The next prime is 16717506565709. The reversal of 16717506565681 is 18656560571761.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16584515063281 + 132991502400 = 4072409^2 + 364680^2 .

It is a cyclic number.

It is not a de Polignac number, because 16717506565681 - 2⁵ = 16717506565649 is a prime.

It is a super-2 number, since 2×16717506565681² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (16717506565621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8358753282840 + 8358753282841.

It is an arithmetic number, because the mean of its divisors is an integer number (8358753282841).

Almost surely, 2^{16717506565681} is an apocalyptic number.

It is an amenable number.

16717506565681 is a deficient number, since it is larger than the sum of its proper divisors (1).

16717506565681 is an equidigital number, since it uses as much as digits as its factorization.

16717506565681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 63504000, while the sum is 64.

The spelling of 16717506565681 in words is "sixteen trillion, seven hundred seventeen billion, five hundred six million, five hundred sixty-five thousand, six hundred eighty-one".