158691 has 12 divisors (see below), whose sum is σ = 229848. Its totient is φ = 97344.

The previous prime is 158663. The next prime is 158699. The reversal of 158691 is 196851.

It is a happy number.

It is not a de Polignac number, because 158691 - 2⁷ = 158563 is a prime.

It is not an unprimeable number, because it can be changed into a prime (158699) 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 11 ways as a sum of consecutive naturals, for example, 351 + ... + 663.

It is an arithmetic number, because the mean of its divisors is an integer number (19154).

2¹⁵⁸⁶⁹¹ is an apocalyptic number.

158691 is a deficient number, since it is larger than the sum of its proper divisors (71157).

158691 is a wasteful number, since it uses less digits than its factorization.

158691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 342 (or 329 counting only the distinct ones).

The product of its digits is 2160, while the sum is 30.

The square root of 158691 is about 398.3603895972. The cubic root of 158691 is about 54.1398978843.

The spelling of 158691 in words is "one hundred fifty-eight thousand, six hundred ninety-one".