158581 has 2 divisors, whose sum is σ = 158582. Its totient is φ = 158580.

The previous prime is 158573. The next prime is 158591. The reversal of 158581 is 185851.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 140625 + 17956 = 375^2 + 134^2 .

It is a cyclic number.

It is not a de Polignac number, because 158581 - 2³ = 158573 is a prime.

It is a super-2 number, since 2×158581² = 50295867122, which contains 22 as substring.

It is a Chen prime.

158581 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (158551) 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 as a sum of consecutive naturals, namely, 79290 + 79291.

It is an arithmetic number, because the mean of its divisors is an integer number (79291).

2¹⁵⁸⁵⁸¹ is an apocalyptic number.

It is an amenable number.

158581 is a deficient number, since it is larger than the sum of its proper divisors (1).

158581 is an equidigital number, since it uses as much as digits as its factorization.

158581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1600, while the sum is 28.

The square root of 158581 is about 398.2222997272. Note that the first 4 decimals coincide. The cubic root of 158581 is about 54.1273855904.

The spelling of 158581 in words is "one hundred fifty-eight thousand, five hundred eighty-one".