17691394081 has 9 divisors (see below), whose sum is σ = 18497226769. Its totient is φ = 16919276836.

The previous prime is 17691394079. The next prime is 17691394093. The reversal of 17691394081 is 18049319671.

The square root of 17691394081 is 133009.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 17691394081 - 2¹ = 17691394079 is a prime.

It is a super-2 number, since 2×17691394081² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (17691394481) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 3056316 + ... + 3062098.

Almost surely, 2^17691394081 is an apocalyptic number.

17691394081 is the 133009-th square number.

17691394081 is the 66505-th centered octagonal number.

It is an amenable number.

17691394081 is a deficient number, since it is larger than the sum of its proper divisors (805832688).

17691394081 is an frugal number, since it uses more digits than its factorization.

17691394081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11612 (or 5806 counting only the distinct ones).

The product of its (nonzero) digits is 326592, while the sum is 49.

Multiplying 17691394081 by its sum of digits (49), we get a square (866878309969 = 931063²).

The spelling of 17691394081 in words is "seventeen billion, six hundred ninety-one million, three hundred ninety-four thousand, eighty-one".