159181681 has 4 divisors (see below), whose sum is σ = 159440292. Its totient is φ = 158923072.

The previous prime is 159181679. The next prime is 159181691. The reversal of 159181681 is 186181951.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5198400 + 153983281 = 2280^2 + 12409^2 .

It is a cyclic number.

It is not a de Polignac number, because 159181681 - 2¹ = 159181679 is a prime.

It is a super-2 number, since 2×159181681² = 50677615131971522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (159181691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 128380 + ... + 129613.

It is an arithmetic number, because the mean of its divisors is an integer number (39860073).

Almost surely, 2^159181681 is an apocalyptic number.

It is an amenable number.

159181681 is a deficient number, since it is larger than the sum of its proper divisors (258611).

159181681 is an equidigital number, since it uses as much as digits as its factorization.

159181681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 258610.

The product of its digits is 17280, while the sum is 40.

The square root of 159181681 is about 12616.7222764076. The cubic root of 159181681 is about 541.9564161611.

The spelling of 159181681 in words is "one hundred fifty-nine million, one hundred eighty-one thousand, six hundred eighty-one".