158681 has 4 divisors (see below), whose sum is σ = 160272. Its totient is φ = 157092.

The previous prime is 158663. The next prime is 158699. The reversal of 158681 is 186851.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 186851 = 7 ⋅26693.

It is an interprime number because it is at equal distance from previous prime (158663) and next prime (158699).

It is a cyclic number.

It is not a de Polignac number, because 158681 - 2⁶ = 158617 is a prime.

It is a super-2 number, since 2×158681² = 50359319522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 158681.

It is not an unprimeable number, because it can be changed into a prime (158611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 635 + ... + 848.

It is an arithmetic number, because the mean of its divisors is an integer number (40068).

2¹⁵⁸⁶⁸¹ is an apocalyptic number.

It is an amenable number.

158681 is a deficient number, since it is larger than the sum of its proper divisors (1591).

158681 is a wasteful number, since it uses less digits than its factorization.

158681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1590.

The product of its digits is 1920, while the sum is 29.

The square root of 158681 is about 398.3478379507. The cubic root of 158681 is about 54.1387606421.

The spelling of 158681 in words is "one hundred fifty-eight thousand, six hundred eighty-one".