159897681 has 6 divisors (see below), whose sum is σ = 230963330. Its totient is φ = 106598448.

The previous prime is 159897649. The next prime is 159897707. The reversal of 159897681 is 186798951.

It can be written as a sum of positive squares in only one way, i.e., 144216081 + 15681600 = 12009^2 + 3960^2 .

It is not a de Polignac number, because 159897681 - 2⁵ = 159897649 is a prime.

It is a super-2 number, since 2×159897681² = 51134536778355522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (159897601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8883196 + ... + 8883213.

Almost surely, 2^159897681 is an apocalyptic number.

It is an amenable number.

159897681 is a deficient number, since it is larger than the sum of its proper divisors (71065649).

159897681 is a wasteful number, since it uses less digits than its factorization.

159897681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17766415 (or 17766412 counting only the distinct ones).

The product of its digits is 1088640, while the sum is 54.

The square root of 159897681 is about 12645.0654802575. The cubic root of 159897681 is about 542.7677751020.

The spelling of 159897681 in words is "one hundred fifty-nine million, eight hundred ninety-seven thousand, six hundred eighty-one".