129561 has 8 divisors (see below), whose sum is σ = 181920. Its totient is φ = 81792.

The previous prime is 129553. The next prime is 129581. The reversal of 129561 is 165921.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 129561 - 2³ = 129553 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (129581) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1080 + ... + 1193.

It is an arithmetic number, because the mean of its divisors is an integer number (22740).

2¹²⁹⁵⁶¹ is an apocalyptic number.

It is an amenable number.

129561 is a deficient number, since it is larger than the sum of its proper divisors (52359).

129561 is a wasteful number, since it uses less digits than its factorization.

129561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2295.

The product of its digits is 540, while the sum is 24.

The square root of 129561 is about 359.9458292577. The cubic root of 129561 is about 50.6008831937.

The spelling of 129561 in words is "one hundred twenty-nine thousand, five hundred sixty-one".