17945013681 has 27 divisors (see below), whose sum is σ = 30157233561. Its totient is φ = 10252686024.

The previous prime is 17945013661. The next prime is 17945013683. The reversal of 17945013681 is 18631054971.

The square root of 17945013681 is 133959.

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

It is not a de Polignac number, because 17945013681 - 2¹⁵ = 17944980913 is a prime.

It is a super-2 number, since 2×17945013681² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (17945013683) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 2809950 + ... + 2816328.

Almost surely, 2^17945013681 is an apocalyptic number.

17945013681 is the 133959-th square number.

17945013681 is the 66980-th centered octagonal number.

It is an amenable number.

17945013681 is a deficient number, since it is larger than the sum of its proper divisors (12212219880).

17945013681 is an frugal number, since it uses more digits than its factorization.

17945013681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12778 (or 6389 counting only the distinct ones).

The product of its (nonzero) digits is 181440, while the sum is 45.

It can be divided in two parts, 179450 and 13681, that added together give a triangular number (193131 = T₆₂₁).

The spelling of 17945013681 in words is "seventeen billion, nine hundred forty-five million, thirteen thousand, six hundred eighty-one".