17945013661 has 2 divisors, whose sum is σ = 17945013662. Its totient is φ = 17945013660.

The previous prime is 17945013631. The next prime is 17945013683. The reversal of 17945013661 is 16631054971.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13071577561 + 4873436100 = 114331^2 + 69810^2 .

It is a cyclic number.

It is not a de Polignac number, because 17945013661 - 2¹¹ = 17945011613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (17945013631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8972506830 + 8972506831.

It is an arithmetic number, because the mean of its divisors is an integer number (8972506831).

Almost surely, 2^17945013661 is an apocalyptic number.

It is an amenable number.

17945013661 is a deficient number, since it is larger than the sum of its proper divisors (1).

17945013661 is an equidigital number, since it uses as much as digits as its factorization.

17945013661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 136080, while the sum is 43.

The spelling of 17945013661 in words is "seventeen billion, nine hundred forty-five million, thirteen thousand, six hundred sixty-one".