17998865645049 has 27 divisors (see below), whose sum is σ = 26393438763237. Its totient is φ = 11819590561944.

The previous prime is 17998865645041. The next prime is 17998865645053. The reversal of 17998865645049 is 94054656889971.

The square root of 17998865645049 is 4242507.

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

17998865645049 is a `hidden beast` number, since 1 + 7 + 9 + 9 + 8 + 8 + 6 + 564 + 5 + 0 + 49 = 666.

It is not a de Polignac number, because 17998865645049 - 2³ = 17998865645041 is a prime.

It is not an unprimeable number, because it can be changed into a prime (17998865645041) 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, 852733354 + ... + 852754460.

Almost surely, 2^{17998865645049} is an apocalyptic number.

17998865645049 is the 4242507-th square number.

17998865645049 is the 2121254-th centered octagonal number.

It is an amenable number.

17998865645049 is a deficient number, since it is larger than the sum of its proper divisors (8394573118188).

17998865645049 is an frugal number, since it uses more digits than its factorization.

17998865645049 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42354 (or 21177 counting only the distinct ones).

The product of its (nonzero) digits is 4702924800, while the sum is 81.

The spelling of 17998865645049 in words is "seventeen trillion, nine hundred ninety-eight billion, eight hundred sixty-five million, six hundred forty-five thousand, forty-nine".