158809681 has 2 divisors, whose sum is σ = 158809682. Its totient is φ = 158809680.

The previous prime is 158809669. The next prime is 158809711. The reversal of 158809681 is 186908851.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 149230656 + 9579025 = 12216^2 + 3095^2 .

It is an emirp because it is prime and its reverse (186908851) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 158809681 - 2¹¹ = 158807633 is a prime.

It is a super-2 number, since 2×158809681² = 50441029558643522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (158801681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 79404840 + 79404841.

It is an arithmetic number, because the mean of its divisors is an integer number (79404841).

Almost surely, 2^158809681 is an apocalyptic number.

It is an amenable number.

158809681 is a deficient number, since it is larger than the sum of its proper divisors (1).

158809681 is an equidigital number, since it uses as much as digits as its factorization.

158809681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 138240, while the sum is 46.

The square root of 158809681 is about 12601.9713140445. The cubic root of 158809681 is about 541.5339114293.

The spelling of 158809681 in words is "one hundred fifty-eight million, eight hundred nine thousand, six hundred eighty-one".