129556161 has 24 divisors (see below), whose sum is σ = 220772864. Its totient is φ = 71642880.

The previous prime is 129556159. The next prime is 129556169. The reversal of 129556161 is 161655921.

129556161 is a `hidden beast` number, since 1 + 2 + 95 + 561 + 6 + 1 = 666.

It is not a de Polignac number, because 129556161 - 2¹ = 129556159 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129556169) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 31216 + ... + 35121.

Almost surely, 2^129556161 is an apocalyptic number.

It is an amenable number.

129556161 is a deficient number, since it is larger than the sum of its proper divisors (91216703).

129556161 is a wasteful number, since it uses less digits than its factorization.

129556161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66381 (or 66378 counting only the distinct ones).

The product of its digits is 16200, while the sum is 36.

The square root of 129556161 is about 11382.2739819423. The cubic root of 129556161 is about 506.0025321833.

The spelling of 129556161 in words is "one hundred twenty-nine million, five hundred fifty-six thousand, one hundred sixty-one".