129581 has 2 divisors, whose sum is σ = 129582. Its totient is φ = 129580.

The previous prime is 129553. The next prime is 129587. The reversal of 129581 is 185921.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 67081 + 62500 = 259^2 + 250^2 .

It is a cyclic number.

It is not a de Polignac number, because 129581 - 2⁶ = 129517 is a prime.

It is a super-2 number, since 2×129581² = 33582471122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 129581.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (129587) 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, 64790 + 64791.

It is an arithmetic number, because the mean of its divisors is an integer number (64791).

2¹²⁹⁵⁸¹ is an apocalyptic number.

It is an amenable number.

129581 is a deficient number, since it is larger than the sum of its proper divisors (1).

129581 is an equidigital number, since it uses as much as digits as its factorization.

129581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 720, while the sum is 26.

The square root of 129581 is about 359.9736101439. The cubic root of 129581 is about 50.6034867694.

The spelling of 129581 in words is "one hundred twenty-nine thousand, five hundred eighty-one".