17966649817 has 2 divisors, whose sum is σ = 17966649818. Its totient is φ = 17966649816.

The previous prime is 17966649809. The next prime is 17966649853. The reversal of 17966649817 is 71894666971.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10155802176 + 7810847641 = 100776^2 + 88379^2 .

It is an emirp because it is prime and its reverse (71894666971) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 17966649817 - 2³ = 17966649809 is a prime.

It is a super-2 number, since 2×17966649817² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (17966649017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8983324908 + 8983324909.

It is an arithmetic number, because the mean of its divisors is an integer number (8983324909).

Almost surely, 2^17966649817 is an apocalyptic number.

It is an amenable number.

17966649817 is a deficient number, since it is larger than the sum of its proper divisors (1).

17966649817 is an equidigital number, since it uses as much as digits as its factorization.

17966649817 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27433728, while the sum is 64.

The spelling of 17966649817 in words is "seventeen billion, nine hundred sixty-six million, six hundred forty-nine thousand, eight hundred seventeen".